The Hornisgrinde, 1,164 m (3,820 ft), is the highest mountain in the Northern Black Forest of Germany. The Hornisgrinde lies in northern Ortenaukreis district.

Vorderlangenbach or Vorderer Langenbach , hamlet of the municipality Baiersbronn , district Freudenstadt, Baden-Württemberg

Bædeker The Rhine from Rotterdam to Constance (1873) Route 46 page 253 mentions the location of a timber sluice.

The village of Zwickgabel is a woodcutter settlement of the 18th century. Since 1932 there is a small Protestant church in Zwickgabel.

From Bædeker's Rhine - 1873, Route 46 page 250

Raumünzach is a residential area in the municipality of Forbach in the northern Black Forest , which was founded in 1775 by forest workers. The settlement with around 30 residents is located on the B 462 and the junction of the L  83 to Hundsbach and the Schwarzenbachtalsperre as well as at the mouth of the mountain stream of the same name into the Murg .

Wikipedia

Forbach is a village in Baden-Württemberg, Germany. It lies in the district of Rastatt. It is located in the Murg river valley, in the northern part of the Black Forest mountains.

From Bædeker's Rhine - 1873: Route 46 page 251

Forbach (Krone conveyances Hirsch and Löwe by the bridge), a thriving village, with a church picturesquely situated on an eminence, is the finest point in the valley. 

At Oberbeuren, 3 M to the E of Baden, the inn of the huntsman's bugle is indicated by a laughing visage, well executed in sandstone, placed above the door.

Bædeker's Rhine - 1873  Route 34 page 200

Oppenau is situated in the Rench valley in the Black Forest. The nearest major cities are Offenburg and Freudenstadt.
Wikipedia

At the Kreuz Inn, near Oppenau, the road to Freudenstadt and Antogast (see below) diverges to the r. At (6 M.) the busy little town of Oppenau (*Stahlbad; Post) “Kirschwasser' is largely manufactured.
Bædeker - Rhine, 1873 page 255

See Bædeker Rhine 1886 page 361

Ottenhöfen im Schwarzwald is a town in the district of Ortenau in Baden-Württemberg in Germany.

This is possibly the town referred to in Twain's journal:
Pretty girl here. An infernal cuckoo clock in hotel where we took dinner Offenbosen 1 1/2 hour before Allerheiligen.

Twain did not like the way of expressing distances by the time taken to get there:
This cursed way of stating all distances by minutes & hours -- it means nothing. You don't know whether it is 15 M by telegraph, or lounging, or with a sheriff after you.

Ebersteinburg is an Ortsteil of Baden-Baden. At 426m in elevation it lies between the valleys of the Murg and Oos rivers. The village has a population of 1,200 and since 1972 has been part of the city of Baden-Baden.

By 1100CE the Counts of Eberstein had taken up residence and constructed Alt Eberstein on top of the hill. Today only the bergfried and shield wall remain intact.

The village itself lies south of the ruins of Alt Eberstein. When the castle fell into decline, the stones were used in the district.