Jackson scored 19 points to lead Danville (11-3), which lost in two straight trips to the All "A" regional finals before getting over the hump and up on the ladder.
"It's different," guard Monica Vonderbrink said. "All you're doing is cutting a little piece of net, but it feels like you just won a state championship.
"To us, it's a big accomplishment. It's great to be up there."
What is shaping up as the best season in school history will continue with a trip to the statewide All "A" Classic in Richmond, where the Lady Admirals will play Covington Holy Cross (15-3) or Newport Central Catholic (13-3) Feb. 4.
It's a remarkable reversal for a program that has endured seven straight losing seasons and has never won a district title.
"This group of seniors has worked so hard for this," Danville coach Justin Schommer said. "They did a lot of extra work in the summer, and they've been playing well all season."
Danville withstood three runs by Monticello
Danville withstood three runs by a determined Monticello team that regrouped after failing to make a basket in the first quarter.
Monticello (5-13) made its final push early in the fourth quarter, erasing a 41-36 deficit to tie the game at 43-all with 5:05 to play.
The Lady Admirals answered with a vengeance, regaining the lead 17 seconds later on a putback basket and free throw by Diamond Smith.
Tasha Milby buried a 3-point basket on their next trip to make it 49-43, and the Lady Trojans never recovered.
Danville pushed its lead to 54-45 with 1:46 left on a jumper by Shatoniah Miller, a steal and layup by Jackson and a free throw by Miller.
Monticello wasted about 45 seconds on the Lady Admirals' next possession before finally fouling, and by then it was too late.
Danville shot 39.6 percent (21-for-53) from the field, while Monticello shot just 33.3 percent (16-for-48) and hit only 10 of 19 free throws. Danville was 8-for-12 at the line.
The Lady Admirals outrebounded Monticello 38-34 overall and 13-3 in the first quarter, when they took a 10-1 lead after the Lady Trojans went 0-for-6 from the field.
DANVILLE (11-3) - Shatoniah Miller 5, Renee Chiu 7, Monica Vonderbrink 8, Krystal Jackson 19, Tasha Milby 10, Diamond Smith 7.
MONTICELLO (5-13) - Audra Turner 10, Sierra Adams 2, Britney Carrender 3, Heather Carrender 2, Meg Phillips 14, Alesia Gehring 4, Erin Foster 7, Rachel Bristow 5.
Renee Chiu, Krystal Jackson, Tasha Milby and Monica Vonderbrink, Danville; Sierra Adams, Meg Phillips and Audra Turner, Monticello; Taylor Bottoms and Bev Harris, Burgin; Caiti Cowan and Madison Flowers, Somerset; Sarah Roach, Harrodsburg.