The 1991 United States Grand Prix was won by Ayrton Senna of McLaren.
The race in United States of America was round 1 of 16 of the 1991 season.
The 1991 United States Grand Prix (formally the XXVIII Iceberg United States Grand Prix) motor was a Formula One race held on March 10, 1991, in Phoenix, Arizona. It was the first round of the 1991 Formula One season. The 81-lap race was won by Ayrton Senna, driving a McLaren-Honda, after he started from pole position. Alain Prost finished second in a Ferrari, with Nelson Piquet third in a Benetton-Ford. It was also the first Formula One race for future double World Champion Mika Häkkinen.
source: Wikipedia
just click on the link and then copy it so you can use it on another website.