Hereford's girls (35) beat over Dulaney (47), Catonsville (73), Loch Raven (78) and Towson (137).
In the boys race, Hereford junior Julian Rivera followed in the winning strides of his brother, Mason, who won county titles in 2009 and 2010, by winning in 16:12.3.
He earned family bragging rights, by clocking a time that was a tad faster than Mason's victorious time (16:17.1) in 2009.
Rivera and classmate Jon Luckin went to the front with Perry Hall's Vince Ciattei for the first two miles, before Rivera pulled away in the final half-mile of the 3.1-mile race.
"I wanted to surge at the end, but Vince was getting ahead, so I had to go," Rivera said. "I wanted to make sure I was strong and decisive, and I just went for it."
Luckin (16:26.5) followed Rivera, with Dulaney's Carus Cookman, Hereford's Kevin Payne, Ciattei, Dulaney's Malcolm Peacock, Hereford's Kevin Collins, Catonsville's Luke Chetelat, Towson's Zach Simmons and Hereford's Gabriel Rivera rounding out the top 10.
Loch Raven senior Emily Ruppel set the pace in the girls race and finished on top in 18:47.2.
Her time was over a minute faster than she ran in the 2010 county championships, when she finished second.
Runner-up Isabel Griffith, a Dulaney sophomore, also ran a strong race and finished in 18:59.2, just over two minutes faster than she ran as a freshman when she placed 16th.
"I could hear her footsteps every time we hit the concrete," Ruppel said. "I swear I could hear the rustling of her bib, and it was driving me insane."
Ruppel knew her closest pursuer would be ready to move late.
"She has quite the kick, so with a half mile to go I started moving, because I thought she would surely get me as soon as we came up the hill," Ruppel said.
Leading the way for the champion Bulls were sophomore Sara Carter (3rd), senior Emily Vandewater (4th), freshman Meghan Anderson (8th), sophomore Erin Causey (9th) and senior Lauren Kennedy (14th).
Causey won the county title in 2010, and Kennedy triumphed in 2009.
Loch Raven's Margaret Glassman (5th), Catonsville's Tara McDonald (6th), Owings Mills' Alyssa Taylor (7th) and Dulaney's Krissy Link (10th) also placed in the top 10.
Boys individual top 15
1. Julian Rivera, Hereford, 16:12.3
2. Jon Luckin, Hereford, 16:26.5
3. Carus Cookman, Dulaney, 16:36.8
4. Kevin Payne, Hereford, 16:37.6
5. Vince Ciattei, Perry Hall, 16:44.1
6. Malcolm Peacock, Dulaney, 16:48.2
7. Kevin Collins, Hereford, 16:53.4
8. Luke Chetelat, Catonsville, 16:54.7
9. Zack Simmons, Towson, 16:57.0
10. Gabriel Rivera, Hereford, 17:07.0
11. Andrew Woodard, Dulaney, 17:13.0
12. Quinn Marvel, Dulaney, 17:16.7
13. Menelik Solomon, Pikesville, 17:22.0
14. Logan Reed, Dulaney, 17:24.1
15. Bradley Franke, Loch Raven, 17:25.4
Girls individual top 15
1. Emily Ruppel, Loch Raven, 18:47.2
2. Isabel Griffith, Dulaney, 18:59.2
3. Sara Carter, Hereford, 19:16.9
4. Emily Vandewater, Hereford, 19:52.4
5. Margaret Glassman, Loch Raven, 19:58.4
6. Tara McDonald, Catonsville, 20:04.7
7. Alyssa Taylor, Owings Mills, 20:09.4
8. Meghan Anderson, Hereford, 20:18.9
9. Erin Causey, Hereford, 20:22.5
10. Krissy Link, Dulaney, 20:25.6
11. Kita Robinson, Dulaney, 20:26.0
12. Sydney Glenn, Dulaney, 20:28.1
13. Caroline Cerand, Catonsville, 20:42.1
14. Lauren Kennedy, Hereford, 20:43.5
15. Jocelyn Corey, Loch Raven, 20:44.2