Are you using a proxy? If so that'd be the reason.
I don't know exactly how far you're talking (UK resident here so my American geography isn't up to scratch!) but failing that then yes, the most likely explanation is because your ISP is based near Admore.
Also bear in mind that some of these "IP locator" tools are just complete crap. There are a few surprisingly good ones around, but for the most part they tend to be very inaccurate and not really worth bothering with! One once told me I was in Ireland...
(No, I don't live anywhere even remotely close to Ireland!)