Question:  The Julington-Durbin Preserve is in the county that has a 2010 population of what?

Context paragraphs:
Julington-Durbin Preserve: The Julington-Durbin Preserve is a 2,031-acre nature preserve operated by the St. Johns River Water Management District in Duval County, Florida.  The preserve shares the name of the two creeks that border the preserve and connect to the St. Johns River.  Julington Creek is on the north side of the preserve, and Durbin Creek is to the south.  The preserve has three designated hiking trails.  Recreational activities include picnicking, horseback riding, bicycling, and hiking.

Marshfield, Wisconsin: Marshfield is a city in Wood County and Marathon County in the U.S. state of Wisconsin.  It is located at the intersection of U.S. Highway 10, Highway 13 and Highway 97.  The largest city in Wood County, its population was 19,118 at the 2010 census.  Of this, 18,218 were in Wood County, and 900 were in Marathon County.  The city is part of the United States Census Bureau's Marshfield-Wisconsin Rapids Micropolitan Statistical Area, which includes all of Wood County (2010 population: 74,749).  The portion of the city in Marathon County is part of the Wausau Metropolitan Statistical Area.

Duval County, Florida: Duval County is a county located in the State of Florida.  As of the 2010 census, the population was 864,263, with a 2016 estimate at 926,255.  Its county seat is Jacksonville, with which the Duval County government has been consolidated since 1968.  Duval County was established in 1822, and is named for William Pope Duval, Governor of Florida Territory from 1822 to 1834.

Vanderburgh County, Indiana: Vanderburgh County is a county located in the U.S. state of Indiana.  As of 2010, the population was 179,703.  The county seat is in Evansville.  While Vanderburgh County was the seventh largest county in 2010 population with 179,703 people, it is also the eighth smallest county in area in Indiana and the smallest in Southwestern Indiana, covering only 236 sq mi.  In 2012, the population was 180,835.

Mentone, Texas: Mentone ( ) is a small town in Loving County, Texas.  As the county's only community, it serves as the county seat and has a 2010 population of 19, almost a quarter of the county's 82 people.  Mentone was until recently the least-populated unincorporated county seat in the United States, but lost that distinction with the 2010 census to Gann Valley, South Dakota, which has a population of 14.  It was designated a Recorded Texas Historic Landmark in 1967 as the "Smallest County Seat in Texas".

Chambersburg, Pennsylvania: Chambersburg is a borough in the South Central region of Pennsylvania, United States.  It is 13 mi north of Maryland and the Mason-Dixon line and 52 mi southwest of Harrisburg in the Cumberland Valley, which is part of the Great Appalachian Valley.  Chambersburg is the county seat of Franklin County.  According to the United States Census Bureau the 2010 population was 20,268.  When combined with the surrounding Greene, Hamilton, and Guilford Townships, the population of Greater Chambersburg is 52,273.  Chambersburg is at the core of the Chambersburg, PA Micropolitan Statistical Area which includes surrounding Franklin County.  The population of the Chambersburg Micropolitan Area in 2010 was 149,618.

Cheyenne, Wyoming: Cheyenne ( or ) is the capital and most populous city of the US state of Wyoming and the county seat of Laramie County.  It is the principal city of the Cheyenne, Wyoming, Metropolitan Statistical Area which encompasses all of Laramie County.  The population was 59,466 at the 2010 census.  Cheyenne is the northern terminus of the extensive and fast-growing Front Range Urban Corridor that stretches from Cheyenne to Pueblo, Colorado, and has a population of 4,333,742 according to the 2010 United States Census.  Cheyenne is situated on Crow Creek and Dry Creek.  The Cheyenne, Wyoming Metropolitan Area had a 2010 population of 91,738, making it the 354th most populous metropolitan area in the United States.

Toms River, New Jersey: Toms River is a township in Ocean County, New Jersey, United States, and the county seat of Ocean County.  Formerly known as the Township of Dover, in 2006 voters approved a change of the official name to the Township of Toms River, adopting the name of the largest unincorporated community within the township.  As of the 2010 United States Census, the township had a total population of 91,239, with the township ranking as the 8th-most-populous municipality in the state in 2010 (after having been ranked 7th in 2000) and the second most-populous municipality in Ocean County (behind Lakewood Township, which had a population of 92,843).  The 2010 population increased by 1,533 (+1.7%) from the 89,706 counted in the 2000 Census, which had in turn increased by 13,335 (+17.5%) from the 76,371 counted in the 1990 Census.

Ocean County, New Jersey: Ocean County is a county located along the Jersey Shore in the U.S. state of New Jersey.  Its county seat is Toms River.  Since 1990, Ocean County has been one of New Jersey's fastest-growing counties.  As of the 2016 Census estimate, the county's population was 592,497, a 2.8% increase from the 576,567 enumerated in the 2010 United States Census, making Ocean the state's sixth-most populous county.  The 2010 population figure represented an increase of 65,651 (+12.8%) from the 2000 Census population of 510,916, as Ocean surpassed Union County to become the sixth-most populous county in the state.  Ocean County was also the fastest growing county in New Jersey between 2000 and 2010 in terms of increase in the number of residents and second-highest in percentage growth.  Ocean County was established on February 15, 1850, from portions of Monmouth County, with the addition of Little Egg Harbor Township which was annexed from Burlington County on March 30, 1891.  The most populous place was Lakewood Township, with 92,843 residents at the time of the 2010 Census (up 32,491 since 2000, the largest population increase of any municipality in the state), while Jackson Township, covered 100.62 sqmi , the largest total area of any municipality in the county.

Waco, Texas: Waco ( ) is a city which is the county seat of McLennan County, Texas, United States.  It is situated along the Brazos River and I-35, halfway between Dallas and Austin.  The city had a 2010 population of 124,805, making it the 22nd-most populous city in the state.  The US Census 2016 population estimate is 134,432 The Waco Metropolitan Statistical Area consists of McLennan and Falls Counties, which had a 2010 population of 234,906.  Falls County was added to the Waco MSA in 2013.  The US Census 2016 population estimate for the Waco MSA is 265,207.

Supporting paragraphs: Julington-Durbin Preserve Duval County, Florida
Answer: 864,263