It was first settled in 1811 by Henry Davidson, then organized as Waldo Plantation on July 6, 1821.

The town was incorporated by the legislature on March 17, 1845, taking the name of its early proprietor.

[3] A large portion of Waldo was rocky and uneven, unfit for cultivation.

Some parts had arable soil, however, producing excellent farms and prosperous farmers.

The Wescott Stream provided water power, and by 1859 Waldo had seven busy sawmills.

[3] In 1870, the Belfast & Moosehead Lake Railroad began operating, its trains passing through the town.

It is bordered by Brooks on the north, Swanville on the east, Belfast on the south and Morrill on the west.

27.7% of all households were made up of individuals, and 6% had someone living alone who was 65 years of age or older.