Great Britain hill-runner Adkin, based in Cumbria these days but representing the Peebles club at the six-mile Callendar Park course, went one better than the silver medal she picked up there last year by going for gold with a time of 27 minutes and 15 seconds.
Edinburgh University Hare and Hounds Running Club’s Alice Goodall was second female finisher in 37:23 and Fife Athletic Club’s Steph Pennycook was third in 38:25.
Gala Harrier Sara Green was fourth woman back in 38:34 and also first veteran competitor over the age of 40 and hot on her heels in fifth was Zoe Pflug, a former member of the Galashiels group but now a clubmate of Goodall, in 38:43.
Adkin broke away after the first of three laps and managed to hold on for victory.
“I did worry a bit that I’d made a move too early,” she said. “Alice was still there throughout the second lap and I think closed a bit at times on the third but I was far enough ahead when we turned into the straight.
“After winning silver last year, it was a good feeling running in towards the finish for the victory.
“I’ve won medals in hill races and, while they are different events and achievements, it’s brilliant to be a Scottish national cross-country champion.
“I’ve been in the sport almost 20 years and came here time after time as a youngster without being anywhere near the medals. I hope there’s a message there for young athletes.”
Gala over-45 Pamela Baillie was the only other Borderer to finish in the top 100 of the 307 women competing, getting back 81st in 46:01.
Her clubmate Darrell Hastie was the first Borderer back and also fastest veteran over 40 in the senior men’s race in 34:58, placing 42nd overall.
He was one of only two representatives of the region in the top 100 of the 672 runners contesting the men’s race, won by Fife’s Logan Rees in 32:09, the other being Gala’s Marcus D’Agrosa, 79th in 36:22.
Gala’s Graeme Murdoch was 165th overall, and fifth over-45-year-old, in 38:54 and his clubmate Ian Maxwell was 430th, and fifth veteran over 60, in 45:29.
The highest-placing junior Borderer on the day was Gala’s Erin Gray. She was tenth in the under-15 girls’ race over 4.3km, contested by 120 runners, in 17:32, with Kirsty Rankine 14th in 17:56 and Ava Richardson 15th in 18:08.
Gala’s Gregor Adamson placed 11th out of 114 under-13 boys racing over 3.2km in 12:32.
That was the same placing achieved by Gala’s Isla Paterson in the under-17 girls’ 6.2km race with 26:21.