Porter County is the site of the Indiana Dunes, an area of ecological significance. A museum called the Hour Glass located in Ogden Dunes, contains exhibits that document the ecological significance.
The area of Indiana, which became Porter County was occupied by an Algonquian people named by the archeologist as the Huber-Berrien. This was a subsistence culture that arrived after the glaciers retreated somewhere around 15,000 years ago and the rise of glacial Lake Algonquian, 4–8,000 years ago. The Huber-Berrien people were a subsistence society. The native people of this area were next recorded during the Iroquois Wars (1641–1701) as being Potawatomi and Miami. The trading post system used by the French and then the English encouraged native people to live in central villages along major waterways. Therefore, there are no recorded villages within the current boundaries of Porter County. It was not until 1830 when Chiqua's town and Tassinong appear on maps and in records. Chiqua's town is located a mile east of Valparaiso on State Route 2,the old Sauk Trail. Tassinong is south of Valparaiso about on State Route 49 at Baum's Bridge Road, the main route across the Great Kankakee Marsh.
Porter County was formed in 1836. From 1832 to 1836, the area that was to become Porter County was part of La Porte County. It was named for Capt. David Porter, naval officer during the Barbary Wars and the War of 1812.