West Branch State Park's large lake with its many forks and coves is extremely popular with fishermen, boaters and swimmers. The park's meadows and woodlots provide an excellent backdrop for camping, hiking and horseback riding.

West Branch State Park in Portage County is situated on the glaciated plateau of northeastern Ohio. Although the land was uplifted as part of the Appalachian Mountain building process, the glaciers were able to override the gentle hills of the plateau. Huge ice blocks broke free from the glaciers and kettle lakes formed as the blocks melted. Eventually, these lakes filled with sediment leaving boggy wetlands with unique assemblages of plants. The West Branch area contains numerous bogs filled with buttonbush, alder, skunk cabbage and swamp white oak.

Another natural feature of the park is the stand of beech-maple forest. In pioneer times, the beech-maple belt in Ohio was very extensive and stretched across the plateau from Mansfield to Pennsylvania. These woodlands harbor a variety of plant and animal life. Woodland wildflowers such as Dutchman's breeches, bloodroot and trillium are found here. Red fox, skunk, opossum and raccoon find the park's habitat suitable. Songbirds occupy the leafy canopy of the woodlands while waterfowl and shorebirds dabble in the reservoir.

West Branch State Park is located on the west branch of the Mahoning River in Portage County. The river was named for the Delaware Indian word mahonink meaning "at the salt lick." In early days, a salt works was located southeast of present-day Warren along the river. The salt, which attracted a variety of wildlife, was harvested by Indians and early settlers.

At the west end of the park is a crossroads known as Campbellsport, named for Captain John Campbell who mustered militia for the War of 1812 at the site and then marched them on Cleveland. Captain Campbell originally came to the area in 1805 as a surveyor and land agent for proprietor Samuel Hinckley. Captain Campbell also served as Portage County sheriff from 1810 to 1813. He constructed what is said to be the oldest brick land-office building in Ohio (circa 1810). Prior to the flooding of the reservoir, this building was moved to a site at the Portage County Historical Society where it has been preserved and restored.

In 1965, the U.S. Army Corps of Engineers completed construction of the Michael J. Kirwan Reservoir. The reservoir was developed for flood control, water supply, recreation and fish and wildlife management. West Branch State Park was formally opened in 1966.

Ohio does not have an annual pass and does not charge entrance fees to state parks.

There are 103 campsites in both sunny and shaded areas. Some sites are along the lake with boat tie-ups. A group camp is available for organizations up to fifty people.