Armstrong, a seven-time Tour de France winner, was staying at Skibo Castle to relax and enjoying some golfing when he posted a message
on Saturday saying he felt a Twitter ride coming on. He then added another stating: "Alright Scotland - it's on. Twitter ride! Meet 5pm tomorrow (Sunday) in Dornoch (Sutherland County) at The Eagle Pub. 30 mile loop."
reported that, according to police, about 300 people took part in the ride.
Many others turned up to see the cyclists.
Armstrong Tweeted after the ride saying, "Thanks Scotland for coming out for a little ride. To the 1000+ who came over Dornoch - you rock! Keep ridin'.." He also posted a message thanking local police for their help.
There was some rain and a few people had accidents when they slipped on the wet ground.
"There was more than 200 cyclists the main street was jammed," commented Highlandcycler on the road.cc
website. "Also there were plent (sic) of people just watching and several along the roadside. All in all a great evening ride although some people did go too far and were cycling far too fast on the small roads and gnerally (sic) acting as if it was a real race, all in all a good ride."
Armstrong posed for photographs and signed autographs before heading back to the castle.
Luckily for those running the pub where the ride finished, news of the event reached them before the thirsty bikers arrived.
"We didn't know anything about this until this morning, fortunately a member of staff is on Twitter and spotted it and then we had to make sure it was real," Gerwain Steele, manager of the Eagle, told The Scotsman
. "Once we realised it was, I called in all the staff to be here from around three o'clock."
Armstrong has organised Twitter rides before, including one in Paisley, Scotland in 2009
. Others were held in Los Angeles, Dublin and Adelaide.
Armstrong was diagnosed with testicular cancer at the age of 25 and is a supporter of the Livestrong