In the year 1600, Mahoning County was likely divided between two nations of Native Americans, the Erie people in the east and the Whittlesey culture in the west.

[6][7] It is unknown where the actual boundaries between these cultures lay, though the nearest confirmed Whittlesey settlement was at Cleveland and the nearest confirmed Erie settlement was just barely across the Ohio-Pennsylvania border, in Ashtabula County.

The Erie were an Iroquoian people who likely arrived sometime between the years 1100-1300 AD, after chasing out an older nation of "Mound Builders.

The tribes who shared the resources of the Mahoning Valley included the Seneca, Lenape (Delaware), Shawnee, and Wyandot.

Some former known Native American sites that existed in Mahoning County include the council rock and the North Benton burial mound.

[9][10] Council Rock was where the Shawnee and Lenape were known to gather for collective holiday celebrations, religion ceremonies and political meetings and once sat in the center of Youngstown.

It was attributed to the Hopewell culture, but contained unique features, such as sculptures of constellations made of white rocks and clay laid out at ground level and a pit full of mixed human bones in one corner.

An extensive German community used to exist in the township of Berlin, until pressure to fully assimilate after the World Wars against Germany ended it.

[citation needed] Circa 1972 to 2016,[25] the majority of voters in Mahoning County and Youngstown chose Democratic Party candidates in U.S. presidential elections.

[citation needed] However in the 2020 U.S. presidential election in Ohio, the majority in those areas selected Donald Trump.

[26] Donald Trump flipped the county Republican for the first time since Richard Nixon's national landslide victory in 1972, carrying it by a margin of 1.9 percentage points.

[citation needed] In the 2024 U.S. presidential election ih Ohio, Trump won the same areas by 13 points.

[citation needed] At the statewide level, Mahoning County generally votes Democratic as well.

School districts include:[28] The population ranking of the following table is based on the 2020 census of Mahoning County.