Border collies win top marks for dog intelligence, but that also means they get bored almost as fast as your mother-in-law when she's finished with her criticisms. If your born herder barks all night, get him good and tired and give him things to occupy his down time.
Discover what's making your pup bark after sundown. Your dog might be barking at sounds coming from the woods or a neighbor's house as a way to ward off potential threats. Border collies are protective of their "herds," or their human families. He might also be barking because he's bored while you're not giving him attention or because he's lonely. It could also be because he's really got to go -- his bathroom is outside, after all -- or because he's hungry or thirsty and looking at empty bowls.
Fix any issues you can before bed. Fill his water or food bowl and make sure he goes out for his evening constitutional right before bed so his bladder won't wake him up. Close exterior doors and windows to help keep the outside noises muted. Give him snuggles and loving before sending him off to bed so he feels like he gets adequate attention.
Exercise with your border one to two hours before you plan to go to bed. Border collies are extremely energetic, requiring tons of play and exercise time. The good news is that a tired border collie is usually a non-barking one. Get him good and worn out with some flying disk time, a good run or by sending him to retrieve a tennis ball.
Buy new toys just for nighttime and change them out at least every couple of weeks. Your border collie likely enjoys puzzle toys that he must flip around to make the treat fall out -- this can keep him occupied and away from boredom before he falls asleep. He can easily become bored with the same old toys, so make sure to give him special new ones often.
Teach your furry friend the "Quiet" command by saying the word when he starts barking. When he stops, pet him and give him a treat. Repeat this process several times a day, and your border collie will be quick to catch on what "Quiet" means. This can be a helpful command when he barks and wakes you up from a deep sleep. Keep a few treats sealed in a bag by your bed so you can reward him when he stops barking.