When did all adult men get given the right to vote?

Note, even in current day, not all adult men can vote. Certain segments of society (former felons being the biggest) are excluded from voting.

From a legal standpoint, the 15th Amendment in 1870 gave all adult men the right to vote. As a practical measure, it was not until the Civil Rights Act of 1964 and National Voting Rights Act of 1965 that most restrictions on universal male sufferage were lifted.