Length 1 – 1 1/4 in. (2.5-3 cm). Although very similar in appearance to the Spring Peeper, the Mountain Chorus Frog has two dark, curved stripes on the back which look like reversed parentheses. On some individuals these lines form a crude “X” or “H” causing it to be easily confused with the Spring Peeper. It also usually bears a dark triangle between the eyes and a white line on the upper lip. Its call is similar to that of the Western Chorus Frog, but distinctly more nasal and higher pitched; with a faster trill rate. This is a woodland species which occurs in Ohio only in the southeastern hill country, often some distance from the water. These frogs are usually inconspicuous, but in late spring they give themselves away as they call from their breeding pools, springs, brooks, or just about any other shallow body of water.
Text courtesy of the Ohio Division of Wildlife: https://wildlife.ohiodnr.gov/portals/wildlife/pdfs/publications/id%20guides/pub348.pdf