A brief history of how the Big Moose Inn was established, as written in the book
Katahdin: An Historic Journey by John Neff:

Millinocket Lake Camps
Irving O. Hunt and his brother Lyman built some rough camps on Millinocket Lake before they became interested in the Nesowadnehunk Stream region. Whether or not their old camps were at the same site as the present camps on Millinocket Lake we do not know.

The Millinocket Lake Camps, known today as Big Moose Inn, are located on a narrow spit of land separating Ambejejus Lake and Millinocket Lake. Before a dam controlled Ambajejus’ water level, it was possible to pole up the short stream from Millinocket Lake into Ambejejus.

Fred Spencer build the camps, originally named Camp Eureka, in 1899 or 1900 and ran them with his brother. With the founding of Millinocket only a few years earlier and lumbering roads nearing Katahdin, the two lakes became more easily accessible. Camp Eureka was advertised as the only camp reachable by both boat (from Norcross) and road (from Millinocket). In 1905, the rate was $1.50 per day, meals included. Spencer also claimed the lakes had no flies or mosquitoes during spring and summer- a phenomenon caused by the way winds blow across the lakes, which makes it difficult for insects to gain a foothold.

The camps’ name changed to Camp Spencer and later to Spencer’s Camps. Around 1929 the lease was transferred to Elmer Woodworth, who lived with his wife on a nearby island while they operated the camps. Elmer, a well-known guide, trapped over the winter, and his wife served as the camp cook. The couple soon renamed the camps Millinocket Lake Camps and Trading Post. They also maintained an outlying camp on Sandy Stream for their guests. In 1941, a major fire broke out in the area. The Woodworths saved the camps by wetting them down, but lost their island home when a stray spark jumped the cove. There is some evidence that, for a short time, a gentleman named Johnny Given either held the lease or managed the camps for the Woodworths. Except for that brief change the Woodworths operated the camps for many years until they passed the lease on to their son Ray, who ran them with his wife Muriel.

In 1977, the lease was transferred to Bob and Frederica (“Teddy”) Boynton, who in 1981 sold the trading post to Erwin and Maureen Bacon. The Boyntons retained the sporting camp operation and later added a public restaurant. Teddy renamed the camps Big Moose Inn. Bob and his son Bruce made many renovations to the camps, while Teddy decorated and furnished them. The Boynton Family has remained involved in the success of the inn and restaurant. After Teddy’s death in 1991, management passed to Bruce and his sister Laurie, but Bob and other family members were still very involved.

The dam separates the flowages of the two lakes. Millinocket Lake is about eight feet above its original level, and Ambajejus is now some 21 feet above its original level. Today several West Branch rafting companies make the Inn their seasonal center of operations.