Eustis is a town located in Franklin County, Maine, within the United States. Situated in the northern part of the state, it serves as a popular recreation area for visitors seeking outdoor activities. The municipality encompasses the village of Stratton and is drained by the Dead River, which flows through its territory. This geographic setting places Eustis in a region known for its natural landscapes and seasonal climate variations.

The area was originally designated as Township No. 1 of Range 4, West of Bingham's Kennebec Purchase. Benedict Arnold and his troops passed through on October 19, 1775, en route to the Battle of Quebec. The first settler, Caleb Stevens, arrived from New Hampshire with his family. In 1831, Charles L. Eustis purchased the northern half and built mills, leading to its organization as Eustis Plantation in 1857 before official incorporation as a town in 1871.

The town is characterized by its rural recreation appeal and historical sites. Key landmarks include the Bigelow Preserve, the Dead River Area Historical Society, and Flagstaff Lake. The village of Stratton lies within Eustis boundaries, contributing to the local community structure. The area offers a mix of natural preserves and historical societies that reflect its deep roots in Maine's frontier history and logging heritage.

Eustis attracts visitors primarily for its recreational opportunities and connection to early American military history. The presence of the Arnold Trail Snowmobile Club highlights its winter sports culture. The town maintains its heritage through local historical societies and preserves, offering a quiet retreat from urban centers. Its appeal lies in the combination of outdoor adventure and the preservation of its unique historical narrative.

According to the 2020 census, the population was 641. The town experiences a humid continental climate with large seasonal temperature differences, featuring warm summers and cold winters. Access is facilitated by its location along the Dead River and surrounding forested areas. The economy supports local recreation and tourism, with the small population reflecting its status as a rural township in Franklin County.