Underwood Spring Park was a 19th- and 20th-century pleasure resort overlooking Casco Bay in Falmouth Foreside, Maine, United States.

[1] Containing an open-air theater, a casino and a gazebo, it was a popular gathering spot serviced by the trolley cars of the Portland and Yarmouth Electric Railway.

The Portland and Yarmouth Electric Railway Company opened the park,[2] located to north of the town landing, on July 18, 1899,[3] to promote the line's service to and from Portland, Maine's largest city, every fifteen minutes.

[4][5] A looped spur off the main line was built the month following the resort's completion to facilitate the ease of passengers' arrivals.

[3] The theater, which was managed by Edward A. Newman,[6] burned down in 1907 and was not rebuilt.