Hamilton is 66 points clear of Ferrari’s Sebastian Vettel, who finished second, with only 75 still available in the remaining three races.
Fifth position in next week’s Mexican Grand Prix will be sufficient for the Mercedes driver to become only the fifth driver in F1 history to claim a fourth championship.
The Briton was beaten off the line by a fast-starting Vettel at the Circuit of Americas but went on to overtake the German for the lead at Turn 12 on lap six.
Despite then building up a substantial lead over Vettel, the Ferrari very nearly undercut Hamilton at the first round of pit-stops, the Mercedes driver only just emerging from the pits in front.
However, Hamilton soon pulled away again and drove off to his 10th victory in 17 races this season, finishing 10 seconds clear.
Elsewhere, Red Bull ‘s Max Verstappen went from 16th on the grid due to grid-place penalties all the way to third, passing Kimi Raikkonen of Ferrari on the final lap of the race.
However, the stewards announced that they were meting out a five-second penalty against Verstappen for gaining an advantage when leaving the track, giving Raikkonen the final podium spot.
United States Grand Prix TOP 10:
1. Lewis Hamilton (Mercedes)
2. Sebastian Vettel (Ferrari)
3. Kimi Raikkonen (Ferrari)
4. Max Verstappen (Red Bull)
5. Valtteri Bottas (Mercedes)
6. Esteban Ocon ( Force India )
7. Carlos Sainz ( Renault)
8. Sergio Perez (Force India)
9. Felipe Massa (Williams)
10. Daniil Kvyat ( Toro Rosso )