Flite,
The clearance you received before departure most likely stated your destination airport as your clearance limit. From the AIM:
4-4-3. Clearance Items
ATC clearances normally contain the following:
a. Clearance Limit. The traffic clearance issued prior to departure will normally authorize flight to the airport of intended landing. Under certain conditions, at some locations a short-range clearance procedure is utilized whereby a clearance is issued to a fix within or just outside of the terminal area and pilots are advised of the frequency on which they will receive the long-range clearance direct from the center controller.
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Normally, when operating in a RADAR environment, that will not change. When landing at an airport where radar service is not available, it is common, but by no means necessary, for the controller to change your clearance limit to a navaid or fix. However, the controller should make PLAIN that your clearance limit has been changed. When I work an arrival, (radar environment), and clear the aircraft direct the LOM, I've not intended to change the airport clearance limit, but only amended the routing to get there. If I'd intended the LOM to be the new clearance limit, I'd also give you holding instruction and an EFC time.
Does that help?