One day in October 1910, a mob of white people in Montgomery, Ala., tried to seize and lynch several black men who were being held in a downtown jail on suspicion of interracial sexual relations.

Unsuccessful, the angry mob found a black man named John Dell sitting nearby in the taxi cab he drove. They shot him dead. No one was prosecuted, and Mr. Dell, as with roughly a dozen other lynching victims in the city’s history, was essentially unacknowledged.

Next year, not far from the site of Mr. Dell’s death, one of the first — and certainly the largest — memorials to the victims of the thousands of racial lynchings in United States history is scheduled to open.

The Equal Justice Initiative, a legal rights organization in Montgomery, is to formally announce the plans on Tuesday.