Question: Which airport is owned by Roosevelt County and is located in a city with a population of 810?

Context paragraphs:
Portales, New Mexico: Portales is a city in and the county seat of Roosevelt County, New Mexico, United States.  The population was 12,280 at the 2010 census.  Portales is located near the larger city of Clovis as well as Cannon Air Force Base, a major contributor to the economy of the region.

Poplar Municipal Airport: Poplar Municipal Airport (FAA LID: PO1) is a public use airport located two nautical miles (4 km) northeast of the central business district of Poplar, a town in Roosevelt County, Montana, United States.  The airport is owned by Town of Poplar.  It is included in the National Plan of Integrated Airport Systems for 2011–2015, which categorized it as a "general aviation" facility.

Wolf Point, Montana: Wolf Point is a city in and the county seat of Roosevelt County, Montana, United States.  The population was 2,621 at the 2010 census.  It is the largest community on the Fort Peck Indian Reservation.  Wolf Point is the home of the annual Wild Horse Stampede, held every year during the second weekend of July.  Wolf Point's Wild Horse Stampede is the oldest rodeo in Montana, and has been called the "Grandaddy of Montana Rodeos".

Dickinson Theodore Roosevelt Regional Airport: Dickinson Theodore Roosevelt Regional Airport (IATA: DIK, ICAO: KDIK, FAA LID: DIK) , formerly known as Dickinson Municipal Airport, is a public use airport located five nautical miles (6 mi, 9 km) south of the central business district of Dickinson, in Stark County, North Dakota, United States.  It is owned by the Dickinson Airport Authority.

Poplar, Montana: Poplar is a city in Roosevelt County, Montana, United States.  The population was 810 at the 2010 census.

Portales Municipal Airport: Portales Municipal Airport (ICAO: KPRZ, FAA LID: PRZ) is a city-owned, public-use airport located four nautical miles (7 km) southwest of the central business district of Portales, a city in Roosevelt County, New Mexico, United States.  According to the FAA's National Plan of Integrated Airport Systems for 2009–2013, it is classified as a "general aviation" airport.

Roosevelt County, New Mexico: Roosevelt County is a county located in the U.S. state of New Mexico.  As of the 2010 census, the population was 19,846.  Its county seat is Portales.  The county was created in 1903 from Chaves and Guadalupe counties and named for President Theodore Roosevelt.  The county's eastern border is the Texas state line.

Roosevelt County, Montana: Roosevelt County is a county located in the U.S. state of Montana.  As of the 2010 census, the population was 10,425.  Its county seat is Wolf Point.  Roosevelt County was created by the Montana Legislature in 1919 from Sheridan County.  The name honors former president Theodore Roosevelt, who had died shortly before the county was formed.

L. M. Clayton Airport: L. M. Clayton Airport (IATA: OLF, ICAO: KOLF, FAA LID: OLF) is a public use airport located three nautical miles (6 km) northeast of the central business district of Wolf Point, a city in Roosevelt County, Montana, United States.  It is owned by the city and county.  The airport is served by one commercial airline, subsidized by the Essential Air Service program.  Reportedly, this made it the smallest airport in the 48 contiguous states with regularly scheduled air service.

Poplar Airport: Poplar Airport (FAA LID: 42S) is a public use airport located in Poplar, a town in Roosevelt County, Montana, United States.  The airport is owned by Town of Poplar and Roosevelt County.  It is included in the National Plan of Integrated Airport Systems for 2009–2013, which categorized it as a "general aviation" facility.

Supporting paragraphs: Poplar Airport Poplar, Montana
Answer: Poplar Airport