Question: At the start of the 20th Century, how many square kilometers was the city that shares a border with the county where William Selden was born?

full_context: Document 1: Richmond, Virginia: By the beginning of the 20th century, the city's population had reached 85,050 in 5 square miles (13 km2), making it the most densely populated city in the Southern United States. In 1900, the Census Bureau reported Richmond's population as 62.1% white and 37.9% black. Freed slaves and their descendants created a thriving African-American business community, and the city's historic Jackson Ward became known as the "Wall Street of Black America." In 1903, African-American businesswoman and financier Maggie L. Walker chartered St. Luke Penny Savings Bank, and served as its first president, as well as the first female bank president in the United States. Today, the bank is called the Consolidated Bank and Trust Company, and it is the oldest surviving African-American bank in the U.S. Other figures from this time included John Mitchell, Jr. In 1910, the former city of Manchester was consolidated with the city of Richmond, and in 1914, the city annexed Barton Heights, Ginter Park, and Highland Park areas of Henrico County. In May 1914, Richmond became the headquarters of the Fifth District of the Federal Reserve Bank.
Document 2: Richmond, Virginia: Richmond is located at the fall line of the James River, 44 miles (71 km) west of Williamsburg, 66 miles (106 km) east of Charlottesville, and 98 miles (158 km) south of Washington, D.C. Surrounded by Henrico and Chesterfield counties, the city is located at the intersections of Interstate 95 and Interstate 64, and encircled by Interstate 295 and Virginia State Route 288. Major suburbs include Midlothian to the southwest, Glen Allen to the north and west, Short Pump to the west and Mechanicsville to the northeast.
Document 3: Richmond, Virginia: Richmond emerged a decade after the smoldering rubble of the Civil War to resume its position as an economic powerhouse, with iron front buildings and massive brick factories. Canal traffic peaked in the 1860s and slowly gave way to railroads, allowing Richmond to become a major railroad crossroads, eventually including the site of the world's first triple railroad crossing. Tobacco warehousing and processing continued to play a role, boosted by the world's first cigarette-rolling machine, invented by James Albert Bonsack of Roanoke in 1880/81. Contributing to Richmond's resurgence was the first successful electrically powered trolley system in the United States, the Richmond Union Passenger Railway. Designed by electric power pioneer Frank J. Sprague, the trolley system opened its first line in 1888, and electric streetcar lines rapidly spread to other cities across the country. Sprague's system used an overhead wire and trolley pole to collect current, with electric motors on the car's trucks. In Richmond, the transition from streetcars to buses began in May 1947 and was completed on November 25, 1949.
Document 4: Richmond, Virginia: Law and finance have long been driving forces in the economy. The city is home to both the United States Court of Appeals for the Fourth Circuit, one of 13 United States courts of appeals, and the Federal Reserve Bank of Richmond, one of 12 Federal Reserve Banks, as well as offices for international companies such as Genworth Financial, CapitalOne, Philip Morris USA, and numerous other banks and brokerages. Richmond is also home to four of the largest law firms in the United States: Hunton & Williams, McGuireWoods, Williams Mullen, and LeClairRyan. Another law firm with a major Richmond presence is Troutman Sanders, which merged with Richmond-based Mays & Valentine LLP in 2001.
Document 5: William Selden: According to the Library of Virginia "William Selden was born 31 January 1791 in Henrico County, Virginia, to Miles Selden (1752-1811) and Elizabeth Armistead Selden (1752-1833). He was a member for Henrico County in the House of Delegates from 1813 to 1816 and from 1818 to 1821. He later served as Registrar of the Land Office. He married first Maria Eliza Swann (d. 1834) 26 November 1833, and they had one child. He married second Emily Hunter 9 June 1840, and they had eight children. Selden died 7 April 1874."
Document 6: Richmond Raceway: Richard Petty holds the record for most wins at Richmond with 13; David Pearson, Darrell Waltrip and Rusty Wallace are tied for second with six.
Document 7: Richmond Field: Richmond Field is a privately owned, public use airport located two nautical miles (4 km) southeast of the central business district of Gregory, a city in Livingston County, Michigan, United States.
Document 8: James Hemings: James Hemings was born into slavery to Betty Hemings, who was the mixed-race daughter of Susannah, an enslaved African mother, and John Hemings, an English sea captain father. James was the second of her six children by her master John Wayles, who took Betty as a concubine after he was widowed for the third time. They had a relationship for 12 years, until his death, and he had a "shadow family" of six children with her. They were three-quarters European by ancestry. Betty had four older children by another man. Wayles died in 1773, leaving Betty and her 10 children to his daughter Martha Jefferson, half-sister to his children by Betty. Martha was then married to Thomas Jefferson, who also inherited them by marriage.
Document 9: William Sutherland of Roscommon: William Sutherland of Roscommon (died 1715), also known as William Sutherland of Mostowie, was a Member of the Parliament of Scotland from 1703 to 1706 and Provost of Elgin from 1705 to 1708. He was son of James Sutherland, 2nd Lord Duffus and married Helen Duff, the eldest daughter of William Duff of Dipple, in 1702. Sutherland owned the estates of Moostowie and Aldroughty. In 1715, his estates were forfeited and he died abroad.
Document 10: William Erasmus Darwin: William Erasmus Darwin (27 December 18398 September 1914) was the first-born son of Charles and Emma Darwin, and the subject of psychological studies by his father. He was educated at Rugby School and Christ's College Cambridge, and later became a banker at Grant and Maddison's Union Banking Company in Southampton. In 1877 he married an American, Sara Price Ashburner Sedgwick (1839 1902). William was a great believer in university education being available to all, and championed the establishment of a university college in Southampton in 1902. The Darwins had no children of their own, and after his wife died, William devoted himself much to his nieces Gwen Raverat, Frances Cornford, and Margaret Keynes. William died on 8 September 1914 at Sedbergh in Cumbria. Raverat remembered him fondly as an eccentric and entirely unselfconscious man in her childhood memoirs "Period Piece" (1952).
Document 11: William Henry Sneed: William Henry Sneed (August 27, 1812 – September 18, 1869) was an American attorney and politician, active initially in Murfreesboro, Tennessee, and later in Knoxville, Tennessee, during the mid-19th century. He was a member of the United States House of Representatives for Tennessee's 2nd congressional district during the Thirty-fourth Congress (1855–1857). In the months leading up to the Civil War, he became a leader of Knoxville's secessionist movement. Along with his successful career as an attorney, Sneed was involved in a number of business ventures, most notably the Lamar House Hotel, which he purchased in 1856.
Document 12: Richmond, Virginia: Richmond is home to the rapidly developing Virginia BioTechnology Research Park, which opened in 1995 as an incubator facility for biotechnology and pharmaceutical companies. Located adjacent to the Medical College of Virginia (MCV) Campus of Virginia Commonwealth University, the park currently[when?] has more than 575,000 square feet (53,400 m2) of research, laboratory and office space for a diverse tenant mix of companies, research institutes, government laboratories and non-profit organizations. The United Network for Organ Sharing, which maintains the nation's organ transplant waiting list, occupies one building in the park. Philip Morris USA opened a $350 million research and development facility in the park in 2007. Once fully developed, park officials expect the site to employ roughly 3,000 scientists, technicians and engineers.
Document 13: Richmond, Virginia: The site of Richmond had been an important village of the Powhatan Confederacy, and was briefly settled by English colonists from Jamestown in 1609, and in 1610–1611. The present city of Richmond was founded in 1737. It became the capital of the Colony and Dominion of Virginia in 1780. During the Revolutionary War period, several notable events occurred in the city, including Patrick Henry's "Give me liberty or give me death" speech in 1775 at St. John's Church, and the passage of the Virginia Statute for Religious Freedom written by Thomas Jefferson. During the American Civil War, Richmond served as the capital of the Confederate States of America. The city entered the 20th century with one of the world's first successful electric streetcar systems, as well as a national hub of African-American commerce and culture, the Jackson Ward neighborhood.
Document 14: Henrico County, Virginia: Richmond Raceway is in the central portion of Henrico County near Mechanicsville, just north of the Richmond city limits. The raceway seats approximately 60,000 people and holds two NASCAR doubleheader race weekends per year. Additionally, Richmond International Airport is located in the eastern portion of Henrico County in Sandston. Top private employers in the county include Capital One, Bon Secours Richmond Health System, and Anthem.
Document 15: Richmond, Virginia: Richmond's economy is primarily driven by law, finance, and government, with federal, state, and local governmental agencies, as well as notable legal and banking firms, located in the downtown area. The city is home to both the United States Court of Appeals for the Fourth Circuit, one of 13 United States courts of appeals, and the Federal Reserve Bank of Richmond, one of 12 Federal Reserve Banks. Dominion Resources and MeadWestvaco, Fortune 500 companies, are headquartered in the city, with others in the metropolitan area.
ground_truth: 13
sub_queries: William Selden >> place of birth Answer: Henrico County
Henrico County >> shares border with Answer: Richmond
How many square kilometers was Richmond at the start of the 20th century? Answer: 13