Question: Juan Carlos Sistos won the Silverston Grand Prix Circuit which straddles where?

Context paragraphs:
2017 Australian Grand Prix: The 2017 Australian Grand Prix (formally known as the 2017 Formula 1 Rolex Australian Grand Prix) was a Formula One motor race that took place on 26 March 2017 in Melbourne.  The race was contested over fifty-seven laps of the Melbourne Grand Prix Circuit and was the first round of the 2017 FIA Formula One World Championship.  The race marked the eighty-first race in the combined history of the Australian Grand Prix – which dates back to the 100 Miles Road Race of 1928 – and the twenty-second time the event was held at the Melbourne Grand Prix Circuit.  The reigning World Champion Nico Rosberg was the winner of the 2016 race, but he did not defend his win as he retired from the sport after the 2016 season.

Silverstone Circuit: Silverstone Circuit is a motor racing circuit in England next to the Northamptonshire villages of Silverstone and Whittlebury.  The circuit straddles the Northamptonshire and Buckinghamshire border, with the current main circuit entry on the Buckinghamshire side.  The Northamptonshire towns of Towcester (5 miles) and Brackley (7 miles) and Buckinghamshire town of Buckingham (6 miles) are close by, and the nearest large towns are Northampton and Milton Keynes.

2014 Australian Grand Prix: The 2014 Australian Grand Prix (formally known as the 2014 Formula 1 Rolex Australian Grand Prix) was a Formula One motor race that was held on 16 March 2014 in Melbourne.  The race was contested over 58 laps of the Melbourne Grand Prix Circuit and was the first round of the 2014 FIA Formula One World Championship.  It marked the début of new Formula One regulations which introduced 1.6 litre turbocharged V6 engines to the sport; the first such instance, since the 1988 Australian Grand Prix, that turbocharged engines have been used in Formula One.  It was the seventy-ninth race in the combined history of the Australian Grand Prix—which dates back to the 100 Miles Road Race of 1928—and the nineteenth time the event was held at the Melbourne Grand Prix Circuit.  The race also marked the thirtieth year that the Australian Grand Prix was run as a round of the Formula One World Championship.

Juan Carlos Sistos: Juan Carlos Sistos is a Mexican racing driver.  He has competed in such series as Euroseries 3000 and the European F3 Open Championship.  In August 2010 it was announced that Juan Carlos had joined Motul Team West-Tec for British Formula 3 and he took a sensational National Class win on his debut at the famous Silverstone Grand Prix Circuit.

1970 Grand Prix (tennis): The 1970 Pepsi-Cola ILTF Grand Prix was a tennis circuit administered by the International Lawn Tennis Federation (ILTF) which served as a forerunner to the current Association of Tennis Professionals (ATP) World Tour and the Women's Tennis Association (WTA) Tour.  It was the inaugural edition of the Grand Prix circuit and consisted of men's tournaments recognised by the ILTF.  The creation of the Grand Prix circuit, on an experimental basis during its first year, was announced in April 1970 by the president of the ILTF, Ben Barnett.  It was the brainchild of Jack Kramer, former tennis promoter and winner of the Wimbledon and US championships, and was aimed at countering the influence of commercial promoters, particularly Lamar Hunt and his World Championship Tennis circuit and George MacCall's National Tennis League.

Buenos Aires Grand Prix (motor racing): The Buenos Aires Grand Prix was a motor race held in Buenos Aires, Argentina.  The event was first held at the Costanera circuit from the early 1930s until 1936 and then continued in 1941 at the Retiro circuit.  After a six-year break and General Juan Peron in office, racing resumed at Retiro in 1947 with the start of the South American "Temporada" Grand Prix series to be contested twice a year under Formula Libre regulations.  Italian Luigi Villoresi won all 1947 Temporada events.  The race regularly attracted Brazilian and European drivers and also Argentine drivers such as Juan Manuel Fangio and José Froilán González were now competing in Europe on a regular basis.  For the 1948 Grand Prix season, the race was moved to the Palermo circuit where it would remain to host six of twelve "Peron Cup" races until the end of 1950.  In 1951, the Costanera Norte circuit would host its last three Grand Prix events before the 1951 completion of the Autodromo 17 de Octubre (October 17), a purpose-built circuit for major Grand Prix series which would host various editions of the Buenos Aires Grand Prix from 1952 until 2009 with the exception of the 1956 event held at the General San Martin circuit in Mendoza.

2013 Australian Grand Prix: The 2013 Australian Grand Prix (formally known as the 2013 Formula 1 Rolex Australian Grand Prix) was a Formula One motor race that was held on 17 March 2013 as the opening round of the 2013 championship.  The race was held at the Melbourne Grand Prix Circuit in the Melbourne suburb of Albert Park.  It was the 78th race in the combined history of the Australian Grand Prix—which dates back to the 100 Miles Road Race of 1928—and the 18th time the event has been held at the Melbourne Grand Prix Circuit.  The race was won by Kimi Räikkönen with Fernando Alonso coming second and Sebastian Vettel coming third.

2016 Australian Grand Prix: The 2016 Australian Grand Prix (formally known as the 2016 Formula 1 Rolex Australian Grand Prix) was a Formula One motor race that was held on 20 March 2016 in Melbourne.  The race was contested over fifty-seven laps of the Melbourne Grand Prix Circuit and was the first round of the 2016 FIA Formula One World Championship.  The race marked the eightieth race in the combined history of the Australian Grand Prix—which dates back to the 100 Miles Road Race of 1928—and the twenty-first time the event was held at the Melbourne Grand Prix Circuit.  Mercedes driver Lewis Hamilton was the defending race winner.

1971 Pepsi-Cola Masters: The 1971 Pepsi-Cola Masters was a men's tennis tournament played on indoor carpet courts of the Coubertin Stadium in Paris, France.  It was the 2nd edition of the Masters Grand Prix and was the season-ending event of the 1971 Grand Prix circuit.  The tournament consisted of a round robin competition for the seven highest points scorers of the Grand Prix circuit.  John Newcombe and Ken Rosewall, players signed to the rival World Championship Circuit but who also took part in several Grand Prix tournaments, had qualified for the event but declined to participate.  The tournament was held from 4 December through 12 December 1971 and was won by Ilie Năstase who earned the $15,000 first prize.

2015 Australian Grand Prix: The 2015 Australian Grand Prix, formally titled the 2015 Formula 1 Rolex Australian Grand Prix, was a Formula One motor race that was held on 15 March 2015 in Melbourne.  The race was contested over fifty-eight laps of the Melbourne Grand Prix Circuit and was the first round of the FIA Formula One World Championship.  The race marked the 80th race in the combined history of the Australian Grand Prix—which dates back to the 100 Miles Road Race of 1928—and the twentieth time the event was held at the Melbourne Grand Prix Circuit.

Supporting paragraphs: Juan Carlos Sistos Silverstone Circuit
Answer: Northamptonshire and Buckinghamshire border