Here’s a look at some of the highlights from day 4 prelims:

Women’s 400m Freestyle

• Katie Ledecky (Bethesda, Md./Stanford Swimming) claimed the top seed for tonight’s final with a 4:02.59. She has won three national championships titles in this event.
• Leah Smith (Pittsburgh, Pa./Cavalier Swimming) follows with a 4:05.98 morning swim. Smith finished second behind Ledecky in the 200m and 800m free and won her first national championships title in last night’s 400m individual medley.

Men’s 400m Freestyle

• 2016 Olympian Clark Smith (Denver, Colo./Longhorn Aquatics) led the field with a 3:49.81.
• Fellow Olympian and University of Texas teammate Townley Haas (Richmond, Va./NOVA of Virginia Aquatics) followed for the second seed. Haas claimed the 200m free national championships title earlier this week.

Women’s 100m Breaststroke

• Reigning Olympic gold medalist Lilly King (Evansville, Ind./Indiana University) claimed the fastest swim of the morning with a 1:06.06.
• Olympic bronze medalist Katie Meili (Colleyville, Texas/New York Athletic Club) followed closely with a 1:06.10.
• Two additional Olympians Breeja Larson (Mesa, Ariz./New York Athletic Club) and Molly Hannis (Santa Rosa, Calif./Tennessee Aquatics) will also compete in the tonight’s final.

Men’s 100m Breaststroke

• Kevin Cordes (Naperville, Ill./Unattached) turned in a 59.16 for the top seed. Cordes has already picked up the national championships titles in the 50m and 200m breast this week.
• Nic Fink (Morristown, N.J./Athens Bulldog Swim Club) grabbed the second seed for tonight. Fink claimed silver in the 200m breast behind Cordes.
• 2016 Olympic bronze medalist Cody Miller (Las Vegas, Nev./Badger Swim Club) will compete as the third seed.

Women’s 100m Backstroke

• Kathleen Baker (Winston-Salem, N.C./Team Elite) turned in a 59.49 Baker was the 2016 Olympic silver medalist.
• 15-year-old Regan Smith (Lakeville, Minn./Riptide Aquatics) held on for the second-fastest swim of the morning. Smith was runner-up in the 200m back.
• 2016 Olympian Olivia Smoliga (Glenview, Ill./Athens Bulldog Swim Club) has qualified as the third-seeded swimmer.

Men’s 100m Backstroke

• Justin Ress (Cary, N.C./Wolfpack Elite) claimed the top time of the morning with a 59.27. Ress won his first national title last night in the 50m back.
• 2016 Olympic gold medalist and world record holder Ryan Murphy (Jacksonville, Fla./California Aquatics) finished with the second-fastest time of the morning. Murphy won the 200m back title earlier this week.
• 2016 Olympian Jacob Pebley (Corvallis, Ore./California Aquatics) and two-time Olympian Matt Grevers (Lake Forest, Ill./Tucson Ford Dealers Aquatics) round out the top four seeds for tonight’s championships final. Grevers has won four national titles in this event.