Guilford Lake State Park is a quiet fishing lake located in northeastern Ohio on the west fork of the Little Beaver Creek. The gentle rolling terrain of the area offers a serene escape for park visitors year round.

Guilford Lake is situated in the glaciated plateau region of Ohio. This portion of the Appalachian foothills was overridden by the glaciers that invaded Ohio more than 12,000 years ago. Eventually, the glacial advances were blocked by the harder and higher sandstone ridges of southeastern Ohio. The bedrock materials of this area were formed 300 million years ago from deposits laid down in streams and swamps.

Natural lakes are a feature of the glaciated landscape, although most in Ohio are very small and have now aged into bogs or marshes. These bodies of water were formed by huge chunks of ice which broke off from the retreating glacier and melted in depressions forming kettle lakes. The area surrounding Guilford Lake, before being impounded as a reservoir, was extremely swampy indicating it may have been a remnant of a natural glacial lake. The park attracts migrating waterfowl in the fall and spring and also provides good habitat for a variety of songbirds such as the red-winged blackbird, song sparrow and eastern meadowlark. Other wildlife common to the area are red fox, raccoon, skunk and white-tailed deer.

The capture of the infamous Confederate general, John Hunt Morgan, near the vicinity of Guilford Lake, ended his gallant raid through the state of Ohio in 1863. Morgan and his 2,000 raiders crossed the entire width of the state from west to east before his eventual capture.

Guilford Lake was constructed as a canal feeder reservoir for the Sandy and Beaver Canal in 1834. An ambitious project undertaken by a private company, the canal was to be 73-miles long and would require two tunnels, thirty dams, ninety locks, three reservoirs and one 400-foot-long aqueduct before it was completed. The park is named after E.H. Gill who was chief engineer of the canal company for several years. He established a road through swampy areas of the present park which became known as Gill's Ford.

When the canal era came to a close, the adjacent landowners breached the embankment in two places and proceeded to use the lake bottom for farmland. In 1927, the land was purchased by the state with the intent of rebuilding the reservoir. The new dam was completed in 1932 by the Division of Conservation. The lake was eventually turned over to the ODNR Division of Parks and Recreation for administration and development. Guilford Lake and Ohio's other canal feeder lakes were the first areas to be dedicated as Ohio state parks in 1949.

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

There is a camping area with 42 electric sites located in an old pine plantation on the northeast corner of the lake,providing shady and sunny areas. A play area, fishing dock, drinking water, showers, flush toilets, picnic tables and fire-rings are provided.