grr!

Okay, so this is my problem:

I live on 45 acres of woodland. My parents own a commercial goat dairy (we are in New Jersey). I am currently boarding my gelding at a local stable. The board fee is pretty expensive, but my parents refuse to let me keep Colby at home because we do not have enough room for a horse.
But here is the thing. In our barn we have one free stall available. It measures 12x24. It is attached to a separate pasture (5 acres of hills and grass).
We also have an uncountable number of trails suitable for a horse and rider, as well as proper fencing surrounding our property and all of our pastures. If you ask me, we have everything we need to accomodate a horse. Even my trainer said so. Why won't my parents let me keep Colby at home?

Have you asked them exactly that - with the logic presented here? While they may say that there reason is the room, they may have other reasons as well. I suggest a calm, collected conversation that you go into with open ears as it will get you much further towards any possible change of mind.

^^ Bravo. Just sit down and talk to them. A lot of people seem to be so hesitant to do that but if you really want something you will do most anything to get it (especially a horse ;)

Ask your parents. Maybe they're concerned about the daily care. Also, have you thought about the fact that horses are herd animals and your boy may do better where he is... around friends?

All the suggestions given i also support :).

Maybe your parents don't want to take on the added responsibility of feeding and caring for your horse the way a boarding facility would.

If I were you, I would lay out your daily plan to feed, water, and clean up after your horse, and present that to your parents in a logical and reasonable manner. Ask them if you could possibly do this as a trial period and then decide later (like, say, a month and if you aren't taking care of the horse like you should, he'll go back to the boarding place).

I hope that helps :)