Mars is a district in Butler County, Pennsylvania, United States. The populace was 1,699 at the 2010 census. Mars is situated in southern Butler County, about somewhere between the urban areas of Pittsburgh and Butler. The little group is settled in a little valley along Breakneck Creek.
The Mars-Evans City Road leads away toward the north.In 1873, Samuel Parks developed a home and a water-controlled gristmill along Breakneck Creek. Parks chose to have a mail station set in his home, so he got assistance from his companion Samuel Marshall to help build up it.