Katie Ledecky, above in Barcelona where she initially set the world record in the 1,500, broke that mark by two seconds Thursday night at a summer tuneup meet in Shenandoah, Tex. (JUANJO MARTIN/EUROPEAN PRESSPHOTO AGENCY)

Katie Ledecky proved Thursday night she doesn’t need an Olympic or world championship pool to set records in. The 17-year-old from Bethesda can do it anytime, anywhere.

The reigning queen of distance swimming began her summer meet schedule by breaking her own world record in the 1,500-meter freestyle by two seconds at the Woodlands Swim Team Senior Invitational Meet in Shenandoah, Tex. — a summer tuneup meet her coach, Bruce Gemmell, added to the schedule because it was convenient.

“I wasn’t really expecting it,” said Ledecky, a two-time All-Met Swimmer of the Year. “I had that feeling where I thought I could go really fast, but I really didn’t think I was going to go anywhere close to the world record.”

A senior in the fall at Stone Ridge School of the Sacred Heart, she finished in a time of 15 minutes 34.23 seconds, beating the old mark of 15:36.53. She did it coming down from altitude after spending 18 days at the Olympic Training Center in Colorado Springs with Gemmell and her Nation’s Capital Swim Club teammates.

This latest world record comes less than a year after Ledecky set two world marks and won four world titles at the FINA World Championships in Barcelona. There, she won gold in the 400, 800 and 1,500 freestyle and 4x200 freestyle relay.

Her swim in Texas was the first time she has competed in the 1,500 since breaking Great Falls-native Kate Ziegler’s world mark in Barcelona by nearly 10 seconds.

“I don’t know if it was easier or harder than in Barcelona,” said Ledecky, who will swim at Stanford. “I got into a great tempo and just tried to keep the pace going on the back half.”

In her past three swims at the mile distance — 1,500 meters or 1,650 yards — she has posted the fastest time in history in the event.

“The mile is such a long race. If you’re going to swim it, you might as well drop a lot of time,” Ledecky joked.

Ledecky, who typically attacks races from the start, took the first 800 meters of the race out in a blistering 8:16, which breaks Janet Evans’s U.S. Open record of 8:17.12, set in 1988 — the second-oldest U.S. long-course mark.

Ledecky will swim seven more events over the next three days in Texas, including the 800 freestyle in which she is the world record holder with a time of 8:13.86.