Jo Konta came through the final round of qualifying but Kyle Edmund suffered a shock defeat to leave six British singles players at the US Open.
Konta beat Austria's Tamira Paszek 6-4 3-6 6-2, taking her winning run since Wimbledon to 13 matches.
Edmund led 5-2 in the final set and had three match points but lost 6-2 0-6 7-5 to Japan's Yoshihito Nishioka.
Naomi Broady lost 7-6 (7-4) 2-6 6-4 to Estonian Anett Kontaveit, Brydan Klein lost 6-3 6-3 to Australia's Matt Ebden.
Konta guarantees herself £26,000 for reaching the first round in New York, where she will face 19-year-old American wildcard Louisa Chirico.
If the 24-year-old comes through that match, she could meet ninth seed and Wimbledon finalist Garbine Muguruza in round two.
Konta joins compatriots Andy Murray, Aljaz Bedene, James Ward, Heather Watson and Laura Robson in the main draw, while Edmund could still qualify as a lucky loser.
The first round at Flushing Meadows gets under way on Monday.
Konta ready to treat herself
It looked as though Konta might have let her chance slip at a break down in the final set against the experienced Paszek.
However, the confidence gained from winning back-to-back titles in Canada shone through as Konta won the last five games to qualify on a baking-hot court 13.
"I've been keeping myself in the present so I haven't been counting the wins," Konta, who also qualified in 2012, told BBC Sport.
"I'm still here. I've just qualified for the US Open and I'm going to enjoy this for what it is.
"We work hard for these moments and I'm looking forward to maybe a burger tonight!"
Edmund gets within one point
The world number 99 was on the verge of completing a significant achievement in his fledgling career by playing in the main draw of all four Grand Slams in 2015.
Edmund had already qualified at the Australian and French Opens this year, winning his first main draw match in Paris as Murray cheered from the stands.
After getting a wild card at Wimbledon, the 20-year-old from Yorkshire looked ready to complete the set in New York.
He fought back from a poor start to build a seemingly impregnable lead against Nishikoka, only for the Japanese player, ranked 127, to see off three match points on serve and win the last three games in a row.