Australia's three representatives, including defending champion Gabi Ruffels, have made a sound start at the weather-hit US Women's Amateur in Rockville, Maryland.

The first phase of the stroke play section began this morning at Woodmont Country Club with a pair of four-under par 68s leading the way for Americans Rachel Kuehn and Riley Smyth.

Ruffels, 20, who this time last year became the first Australian to win a US Women's Amateur, had two birdies and two bogeys in her opening 72, even-par, which left her in a tie for 15th, a position that left her satisfied given the expectations on her shoulders.

"There was extra pressure, extra nerves, especially with the whole year that's been going on," Ruffels said.

"It's been a long wait to get here, but I'm happy with how I did today and how I handled those first-round nerves."

The top 64 players from the 132-player field at the end the second round of stroke play will progress to the match play phase, but that round will be delayed a day with expected wild weather from tropical storm Isaias tomorrow having forced the USGA's hand.

The other Australians, Kirsty Hodgkins and Emily Mahar both shot opening 73s and are tied 24th.

Mahar, who had Virginia Tech teammate Jessica Spicer as her caddie, was happy to have completed her round after weather delays.

She was also excited to continue her good form after reaching the Round of 16 at the recent North and South Amateur at Pinehurst.

"I've improved a lot this year and was actually playing really well when college ended (with the pandemic), so that was disappointing," the Queenslander said.

"So I spent three months slowly working away at home and came back at out at North & South and I'm very happy."

Mahar, in her senior year with the Hokies, might have been up the leaderboard much further had she experienced any luck with the putter today.

"Jess and I were reading all these putts together and I reckon in my 15 pars today, I must have have 12 or 13 one-inch tap-ins," she said with a wry giggle.

"If some of them go in, who knows? But yeah, I'm happy to be playing well (when it counts)."

Hodgkins, a senior at the University of Colorado, was three over for much of her round after starting on the 10th, but made birdies on the sixth and eighth holes late in her round.

US Women's Am scoring