The first business in Plentywood opened in 1900, and a post office was established two years later. The city incorporated in 1912, following the arrival of a Great Northern Railwaybranch line that eventually ran from Bainville to Opheim. Local folklore suggests that the name of the nearby Plentywood Creek, after which the city was named, comes from a search for firewood. One day, according to the story, a group of cowboys watched in exasperation as the chuck wagon cook attempted to start a fire with damp buffalo chips. Finally, in frustration, Dutch Henry said, "If you’ll go 2 miles up this creek, you’ll find plenty wood." Plentywood has been a center for purchase of pulse crops since 2005.
As of the census of 2010, there were 1,734 people, 820 households, and 462 families residing in the city. The population density was. There were 972 housing units at an average density of. The racial makeup of the city was 95.0% White, 0.2% African American, 1.7% Native American, 0.7% Asian, 0.3% from other races, and 2.1% from two or more races. Hispanic or Latino of any race were 2.1% of the population. There were 820 households of which 22.2% had children under the age of 18 living with them, 45.2% were married couples living together, 7.1% had a female householder with no husband present, 4.0% had a male householder with no wife present, and 43.7% were non-families. 40.6% of all households were made up of individuals and 18.6% had someone living alone who was 65 years of age or older. The average household size was 2.02 and the average family size was 2.68. The median age in the city was 49.7 years. 19.1% of residents were under the age of 18; 5.3% were between the ages of 18 and 24; 18.7% were from 25 to 44; 32.4% were from 45 to 64; and 24.5% were 65 years of age or older. The gender makeup of the city was 47.8% male and 52.2% female.
2000 census
As of the census of 2000, there were 2,061 people, 857 households, and 522 families residing in the city. The population density was 1,756.1 people per square mile. There were 1,020 housing units at an average density of 869.1 per square mile. The racial makeup of the city was 97.14% White, 0.97% Native American, 0.15% African American, 0.19% from other races, and 1.12% from two or more races. Hispanic or Latino of any race were 1.12% of the population. There were 857 households out of which 27.7% had children under the age of 18 living with them, 53.2% were married couples living together, 5.7% had a female householder with no husband present, and 39.0% were non-families. 36.3% of all households were made up of individuals and 19.4% had someone living alone who was 65 years of age or older. The average household size was 2.26 and the average family size was 2.95. In the city, the population was spread out with 23.3% under the age of 18, 4.5% from 18 to 24, 23.0% from 25 to 44, 23.7% from 45 to 64, and 25.5% who were 65 years of age or older. The median age was 44 years. For every 100 females there were 88.7 males. For every 100 females age 18 and over, there were 85.8 males. The median income for a household in the city was $30,037, and the median income for a family was $37,679. Males had a median income of $24,741 versus $20,662 for females. The per capita income for the city was $15,609. About 10.6% of families and 16.3% of the population were below the poverty line, including 14.0% of those under age 18 and 19.1% of those age 65 or over.
Radio
Plentywood is home to "Radio International", with the combined signals of KATQ 1070, KATQ-FM 100.1, and KATQ-FM 107.1. All stations are located at 112 Third Avenue East. The stations serve the northeast Montana, western North Dakota and southern Saskatchewan region.
Schools
In 1969 Plentywood played Choteau and lost in its first Class B boys state championship basketball appearance. The 1976 boys basketball team won the Montana Class A title against Hamilton as one of the smallest Class A teams in the state at the time. In 1978, the boys basketball team won the Class B title against Big Timber after declining enrollment resulted in a downward classification. The 1979 boys basketball team finished as runners-up to the archrival Scobey Spartans at the State B Boys Basketball Tournament. The 2007 boys basketball team finished again as runners up but this time it was to Huntly Project at the State B Boys Tournament. In 1998 the Wildcats finished 3rd at the State Tourney and in the 1980s had a pair of top 4 finishes at the State Tournament as well. The 1971 Plentywood Wildcats football team, coached by Doug Dierenfield, made it to the class B state championship losing in overtime 6-8 to Huntley Project. The 1981 Plentywood Wildcats football team, coached by Ron Smith, beat the Big Timber Herders 20-14 for the State B title in Big Timber. Ron Smith is the only coach in Sheridan County to have ever won a State Football title. In 1997 the Plentywood Wildcat football team also made it to the state championship losing to Frenchtown 27-20 after being up 20–7 at halftime. The 1999 and 2000 Girls' Golf Team won the State B-C title. For 5 years from 1997-2001 Plentywood was the state champion girls' 4x400 relay winner In 1977 Plentywood won the Class B State Championship in Boys Cross Country. Cross Country was later dropped from the athletic program. The Plentywood Boys Track team has won four State Titles: 1970, 1971, 1972 and 1973.
Athletics
A number of stand out athletes have competed in Plentywood. Zoonie McLean Jr. was starting quarterback for the Montana State Bobcats in the late 60's and early 70's. Ron Marsh was a standout track and field/football player for PHS. He participated in the East/West Shrine Game his senior year and after that attended Minot State College. The 6–1, 245-pound defensive end earned All-Conference and All-District titles while playing his senior year in 1981. He also was chosen for the Honorable Mention All-American title. After his senior year he signed with the Denver Broncos. Former University of Montana Grizzly basketball coach Don Holst is a PHS graduate as is former University of Montana assistant football coach Kraig Paulson. Long time University of Montana Grizzly women's basketball coach Robin Selvig is a native of nearby Outlook and his first teaching job was at Plentywood High School.
Climate
Plentywood experiences a semi-arid climate with long, cold, dry winters and hot, wetter summers.
