James Jerome Hill, primary stockholder and president of the St. Paul, Minneapolis & Manitoba Railway (StPM&M), established the Montana Central Railway on January 25, 1886. Few railroads served Montana at that time. But Butte, Montana, was a booming mining town that needed to get its metals to market; gold and silver had been discovered near Helena; and coal companies in Canada were eager to get their fuel to Montana's smelters. Hill had already decided to build the StPM&M across the northern tier of Montana, and it made sense to build a north-south railroad through central Montana to connect Great Falls with Helena and Butte. Another reason for building the Montana Central was Hill's investment in the city of Great Falls. Hill's close friend and business associate, Paris Gibson, had founded the town of Great Falls on the Great Falls of the Missouri River in 1883, and was promoting it as a site for the development of cheap hydroelectricity and heavy industry.

Hill organized the Great Falls Water Power & Townsite Company in 1887, with the goal of developing the town of Great Falls; providing it with power, sewage, and water; and attracting commerce and industry to the city. To attract industry to the new city, he offered low rates on the Montana Central Railway. Surveyors and engineers began grading a route between Helena and Great Falls in the winter of 1885-1886 (even before the company had been incorporated), and by the end of 1886 had surveyed a route from Helena to Butte. Construction on the Great Northern's line westward began in late 1886, and on October 16, 1887, the link between Devils Lake, North Dakota; Fort Assinniboine; and Great Falls was complete. Service to Helena began in November 1887, and Butte followed on November 10, 1888. On September 18, 1889, Hill changed the name of the Minneapolis and St. Cloud Railway (a railroad which existed primarily on paper, but which held very extensive land grants throughout the Pacific Northwest) to the Great Northern Railway. On February 1, 1890, he transferred ownership of the StPM&M, Montana Central, and other rail systems he owned to the Great Northern.

See The Montana Central Railway 

From Great Falls to Craig:
The first 50 miles of the line followed the west bank of the Missouri River from one mile south of the Sun River crossing near Great Falls to Craig. Most of the grade work was done during the fall of 1886 and with few exceptions conformed to the gradient of the river. The line was ironed in about 30 days and put into service November 19, 1887.

From Craig to Helena:
The second 50 miles of the line followed Little Prickly Pear Creek to the summit at Silver, then descended into the Helena Valley, crossed the NP west of town and climbed into the terminal grounds on lower Last Chance Gulch. Most of the preparation work was done in 1886, and the gradient seldom exceeded one percent. The line was put into service also on November 19, 1887.

From Helena to Clancy:
The first 5.9 miles of the line south of Helena paralleled the NP to East Helena (originally called Easton, the Four Range). The road then turned south, climbing along Prickly Pear Creek to Alhambra. Here it paralleled the Helena Jefferson County RR built in 1883 to reach Wickes.

Ulm:
Originally a large ranch owned by Indiana-born cattleman William Ulm.

Cascade:
The town of Cascade grew out of several other communities near the present site of Cascade. On the east side of the Missouri, a small town named Ulida developed at the ferry (nicknamed "The Mayflower") for the Chestnut Valley freight and stage route. In l 879, George Steele opened a store in this new settlement. In 1885, the name was changed to Gorham. At that time Thomas Gorham, who later opened a store across the river, managed the Steele Store. In 1886, the land was sold to James and Mary Erskine, and in 1889 the town name was changed to St. Clair after the couple's baby who had just died. This small town flourished -- residents built homes, and the Rev. Little started the Methodist church in 1889. It's believed that the St. Clair school was held in the living room of the log cabin parsonage. A Chinese family ran a restaurant in Steele's store.

In 1886, the Montana Central started building its tracks from Great Falls on the west side of the river. Starting as a railroad-crew town, a new settlement named Dodge appeared, complete with a post office run by Thomas Gorham as postmaster. When the railroad was completed in 1887, the name was changed to Cascade. Just two months before, the Territorial Legislature established Cascade County from parts of Meagher, Choteau, Lewis and Clark, and Fergus.Before this action, the Missouri had divided Lewis and Clark County from Meagher County.
http://www.cascademontana.com (link to /historycc.htm broken)

Tunnel #1, Green's Tunnel:
600 feet long and particularly difficult to build. It was excavated by crews working for contractors W.H. Green and A.K. Barbour. At 1:30 am, August 12th a block of stone six feet thick came loose from the ceiling. This in turn dislodged 20 feet of the tunnel's roof, crushing Jack Hayes, Joe Bush and Sam Tillerby who were busy installing timber lining. Four other men were injured and evacuated to Helena.
Taylor pp 47-54.

Hardy Creek:
Hardy Creek lies approximately eight miles south of Cascade, nearly half-way between Helena and Great Falls. Named for Rufus Hardy who came to the area in 1866, the small settlement was little more than a railroad siding for passenger and mail delivery and pickup. Hardy had its own post office 1888 and its own school in 1895.

Mid Canon:
A siding.

Wolf Creek: A River Runs through it.
Nestled deep in the Big Belt Mountains in one of the most spectacular canyons in Montana, Wolf Creek was established as a stop along the Montana Central Railroad.Wolf Creek reportedly got its name from a local Indian legend that stated when the buffalo were being driven over a nearby cliff to their death, a wolf went along for the ride.They named the creek that flowed by the cliff "the creek where the wolf jumped too" or "the creek that the wolf jumped in. Prior to Wolf Creek being established, there was a town called Cartersville founded where Little Wolf Creek empties into Little Prickly Pear Creek.Wolf Creek grew from Cartersville to serve the railroad. The Wolf Creek Hotel, built in 1887, ;served as a stage stop along routes from Helena to Augusta and Fort Benton. Two cabins served as railroad housing. Prior to the construction of the railroad, the first road constructed through the canyon was a toll road built in 1865 by the Little Prickly Pear Wagon Road Company. By the early 1870's, the road was an important freight and passenger route in the territory.
https://wolfcreekangler.com/brief-history-wolf-creek-montana/

Silver City:
The first county seat of Lewis and Clark County.
History of Montana. 1739-1885: A History of Its Discovery and Settlement ...
edited by Michael A. Leeson

Helena:
By 1888, about 50 millionaires lived in Helena, more per capita than in any city in the world. They had made their fortunes from gold. About $3.6 billion (in today's dollars) of gold was taken from Last Chance Gulch over a 20-year period. The Last Chance Placer is one of the most famous placer deposits in the western United States. Most of the production occurred before 1868. This large concentration of wealth was the basis of developing fine residences and ambitious architecture in the city; its Victorian neighborhoods reflect the gold years. The numerous miners also attracted the development of a thriving red light district. Among the well-known local madams was Josephine "Chicago Joe" Airey, who built a thriving business empire between 1874 and 1893, becoming one of the largest and most influential landowners in Helena.
https://en.wikipedia.org/wiki/Helena,_Montana

East Helena:
In 1888, a large lead smelter was built on the banks of Prickly Pear Creek in the Helena Valley by the Helena and Livingston Lead Smelting Company. In 1898, the American Smelting and Refining Company (ASARCO) purchased the 160 acre site. ASARCO operated the smelter until 2001. East Helena grew up around that enterprise. For over a century, the smelter processed 70,000 tons of lead bullion a year, and provided a livelihood for thousands of families. It also produced untold tons of toxic contaminants.
http://www.helenahistory.org/east_of_helena.htm

Montana City:
Montana City is located on top of one of the oldest prehistoric sites in the state of Montana. As early as 9,000 BCE, Native Americans came to Montana City to collect chert, a rock similar to flint which was used to make spear tips, arrowheads, and knives. White American explorers discovered gold at the site on July 2, 1862, and later that year United States Army Captain Jason L. Fisk brought a mule train from Minnesota which stopped at the site and built the first houses that became Montana City.The town became one of the most important mining centers in Montana during the height of the gold rush in the 1860s.The Montana Town Company laid out the city in 1864, naming it after the state's new territorial name.Chinese miners took over from whites when the mines began to play out in 1868, and the town saw a brief revival after the arrival of the railroads and the establishment of a post office in the 1880s. At its height in the 1880s, Montana City had 3,000 residents and competed for the location of the state capital.
https://en.wikipedia.org/wiki/Montana_City,_Montana

Clancy:
Clancy boomed in the 1870s as a silver placer mining camp and quickly absorbed nearby towns like the once prosperous Prickly Pear City. When the silver diggings dwindled in the 1890s, Clancy would have died too, were it not for the efforts of Henry Hill, a Clancy resident. Hill had helped to establish Montana's first woolen mill in Clancy in 1879, [and in 1896 he built a railroad yard on his ranch, which he sold to the Montana Central.]
http://southwestmt.com/communities/clancy.htm

Alhambra:
Alhambra was a resort town situated South of Helena and relied on the heavy traffic during the golden days of mining in the area. Alhambra and Sunnyside Hot Springs were the two hotels in the town, together composing a medical and recreational resort that flourished in the 1860s until the 1950s. Alhambra Hot Springs consists of four main springs and a number of hot water seeps located along Warm Springs Creek. The water temperature averages 138 degrees F. and is slightly radioactive.
https://en.wikipedia.org/wiki/Alhambra,_Montana

Corbin:
Corbin was an important mining town in the 1890s and included a stamp mill and heavy infrastructure for the time which yielded decent amounts gold and silver. Alta Mine in particular, was a major silver mine in the area which the town developed around. A post office was active in Corbin from 1887 until 1943.
https://en.wikipedia.org/wiki/Corbin,_Montana

Wickes:
The silver mines around Wickes were among the earliest developed in Montana. The first mine, the Gregory, was located by an unknown prospector in 1864 and was the site of the second silver smelter built in Montana in 1867.
Discovered in 1869, the Alta proved to be one of the richest silver mines in Montana. In 1876, its original owners sold the property to a group of New York capitalists head by William W. Wickes. The cartel organized the Montana Company that same year and platted the community of Wickes in either 1876 or 1877. The camp had around 400 residents by 1880.

The community of Wickes was a booming, although atypically quiet, mining camp by mid-1880. The Weekly Herald reported that: "No liquor is allowed in the camp, and any employee who becomes intoxicated loses his place at once. The consequence is that but a small part of the dissipated element which is ordinarily found in a mining settlement of this kind is represented here." Regardless, the camp boasted a public library and the firm of Vawter & Wickes built a substantial stone building that sold "everything which the people of the camp required."

The Alta Mine was the centerpiece of the district. It consisted of three tunnels, the deepest of which reached 250-feet below the surface of Alta Mountain (the mine eventually bottomed out 1,600-feet below the adit.) The mountain was reportedly honeycombed by 30 miles of tunnels, shafts and stopes. By 1889, the mine was the largest producer in the Wickes-Corbin Mining District.
In 1882, disaster struck the Alta Company when a fire destroyed the mill. As a result, the company was forced to sellout in 1883 to one of its stockholders, Sam Hauser.

Operating through the Helena Mining and Reduction Company (HMRC), Hauser paid off the Alta Company's $250,000 debt and spent over $90,000 rebuilding the entire silver mill. He added two new concentrators and six new charcoal kilns. The kilns could produce over 25,000 bushels of charcoal a month. In 1884, the HMRC constructed a new smelter, one of the largest of its kind in Montana Territory. The new smelter included three large masonry smokestacks that eventually came to symbolize the Wickes operation. Most importantly, Hauser induced the Northern Pacific Railway to construct a branch line between Helena and Wickes.

Wickes was one of six communities to be listed in the territory's first telephone directory in 1885. The Rocky Mountain Bell Telephone Company served nine customers in Wickes until the telephone exchange closed in 1886. One pundit later claimed that "(playing) cards strewed the Main street so thickly that for several years a man with a team cleared the street every morning."

The community received another boost in 1886, when Jim Hill and Charles Broadwater completed their Montana Central Railroad between Great Falls and Butte. Like many of its bigger sister cities, Wickes could then claim it had two railroad depots. The expansion of the mines at Wickes spread through the district causing the establishment of other mining camps. The most important, Corbin was platted in 1883 and claimed 100 residents the following year. The Wickes-Corbin Mining District thrived until 1889, when the HMRC dismantled the Wickes smelter and moved it to East Helena. From then on, the ore was shipped by railcar for processing at either East Helena or Butte. The Alta Mine operated for another seven years before it, to, closed.
https://en.wikipedia.org/wiki/Wickes,_Montana

Boulder Tunnel (Tunnel #6):
6,115 feet long, the longest tunnel on Hill's railroads until 1929. Contractors began work in March of 1887, and the first train passed through ;October 25, 1888. Eleven men were killed during its construction. ;Until it was finished, the Montana Central used the Northern Pacific line over Boulder Hill. Northern Pacific later abandoned their own line from Clancy to Amazon in lieu of trackage rights through the tunnel. By 1891 the tunnel's wooden lining was replaced with brick and granite, a six foot wide steel beam was inserted in the ceiling. During 1882 and 1883, the railroad was again detoured. Portals were added to the tunnel in 1893, extending the tunnel by 30 feet. Doors at both ends of the tunnel prevented ice build up.
see Taylor page 80.

Boulder City:
Named for the many large boulders in the vicinity, the town of Boulder Valley was established in the early 1860s as a stagecoach station on the route between Fort Benton and Virginia City. It later became a trading center for nearby agricultural areas and the Elkhorn, Comet, and Baltimore mining districts. The Great Northern Railway branch line from Helena to Butte reached Boulder in 1888. State schools for the deaf, blind, and developmentally disabled were established in the city in 1892.
https://en.wikipedia.org/wiki/Boulder,_Montana

Basin:
The town of Basin began as a 19th century mining camp near the confluence of Basin Creek with the Boulder River. Gold deposits at the mouth of Cataract Creek, about 0.5 miles (0.8 km) downstream of Basin were reported as early as 1862. Prospectors staked claims and built cabins, and within a few years placer mining extended the full lengths of Cataract and Basin Creeks. When a settlement was established in Basin, the buildings at the mouth of Cataract Creek were gradually moved to Basin, and the Cataract camp was abandoned. Searches for the lode veins on both creeks succeeded by the 1870s and eventually led to significant lode mining at the Eva May, Uncle Sam, Grey Eagle, Hattie Ferguson, and Comet mines in the Cataract Creek district and the Bullion, Hope, and Katy mines in the Basin Creek district. By 1880, the settlement at Basin became the local source of supplies for mines and miners.

Wilder & Tunnels 8 and 9:
Montana Central Railroad reached Bernice, five miles west of Basin, in June 1888. While never a town, several mines were located on the hillside above Bernice, and Lake Wilder was only two miles south. Just across the Boulder River was the stage station at Calvin's Ranch. Bernice was a water stop for southbound trains and it housed a section gang. For a time there were charcoal kilns there that supplied fuel to the region's mills. Passenger trains brought Butte families to Wilder to enjoy fresh air and scenery on the man-made lake.
see Taylor pg 90

Elk Park:
February 27, 2012 12:00 am By John Grant Emeigh of The Montana Standard
Elk Park, the 10-mile long valley north of Butte, boasts a colorful history of providing the Mining City with everything from milk to moonshine. The area was known for its cattle ranching, dairy production, ice making, logging and even some less-than-legal activities: Almost every ranch in Elk Park operated a still to make liquor during Prohibition. "Everybody had a copper cow". Folks also had real cows and produced more wholesome products of milk and other dairy items. Most of the early settlers were of Swiss ancestry, and brought dairy skills with them. They would cart the milk down to the Mining City each day. During hard times in Butte the Elk Park dairy farmers gave milk to families that couldn't pay. "They knew the milk was going to go bad anyway, and they'd rather have a child have the milk and let the family pay them back later".

Elk Park Pass, elevation 6,352 ft (1,936 m), is a mountain pass on the Continental Divide. Elk Park Pass lies on the border between Silver Bow and Jefferson counties and is remarkable for its highly asymmetrical nature. 
The approach from the north is through namesake Elk Park, a high, mostly treeless plain, and the grade is almost imperceptible: The elevation at the northeast end of the park, about 10 miles (16 km) from the pass, is about 6,200 ft (1,900 m), only 152 ft (46 m) lower than the pass itself. However, at the south end, the highway drops 750 ft (230 m) from the pass into Butte over a distance of only about 4 miles (6.4 km).
https://en.wikipedia.org/wiki/Elk_Park_Pass