The location of Mark Twain's lecture in Akron, OH on December 30, 1868 is noted as the Methodist Church.  The location and name of the site in 1868 has not been definitively determined but one possibility is ...

The Universalist's Old Stone Church is gone, but the Sojourner Truth
Building in its place is named for an event that put Akron on the civil-rights map.

On May 29, 1851, the church hosted the second Woman's Rights Convention. There, former slave Sojourner Truth electrified the gathering with her “And Ain't I A Woman?” speech, in which she compared her physical and mental attributes to those of a man.

A dozen years later, after Truth became a nationally recognized
suffragette and abolitionist, the 1851 convention president, Francis Dana Gage, published her recollection of Truth's speech.

While Gage said Truth had rhythmically repeated ‘and ain't I a woman,‘ many historians have come to believe Gage made up that phrase.

Regardless, Truth's Akron speech was turned into a battle cry that
empowered the civil-rights movement for decades.

https://www.downtownakron.com/community/downtown-history/street-stories-high-street

This is currently the location of the Sojourner Truth Building