I live in California and am purchasing undeveloped land in Missouri to move to when I retire. The company that holds my loan for the land notified me that someone notified them that people are living on the land. I have given no one permission to be there. There are no permanent structures on the property so I am assuming they put a trailer on it. The property is semi-rural. What do I do to get these people out without having to fly out there myself? Thank you in advance.

What category of loan/purchase is it?
If you haven't purchased it yet, you refuse to close until it's empty. Demand a video tour of 5 uncut minutes and someone holding up today's newspaper.
'Am purchasing' implies that you haven't closed - it isn't yours.
If you are paying a loan in advance, that is a risky idea long distance. The burden is on you to track down the 'loan company' or 'seller' if they take off with your money, and you have no deed for the land.
I hope this is land you can actually get power to and water under? Tons of the US is cheap and useless because it is impossible to develop a house on.

Thank you for your reply but you misunderstood. The land is already in my name and I pay the property tax. The loan is no different than the mortgage you would pay on your house and yes there are utilities on the land. I am not familiar with the laws of Missouri and thought someone on this site might be.

Had to clarify first, because you said 'am purchasing' instead of 'purchased.'
http://www.evictionresources.com/eviction_process_articles/missouri_eviction_process.html

Your best option is to hire someone to handle this. It could be a lawyer, or anyone. Ask the loan company. Ask the local police if they have a retired officer.

Your question was a bit ambiguous.

But I would contact the local sheriff or police department. These are trespassers and the polices should remove them. Are there no trespassing signs on the property?

Since this is undeveloped land, I don't think this is an issue of eviction. Did you ask the lender how they know about them?