Are your maps using the same datum as your GPS (WGS 84)? That is likely the source of the discrepancy. If they are using the same datum, I suspect your maps are

Are your maps using the same datum as your GPS (WGS 84)? That is likely the source of the discrepancy. If they are using the same datum, I suspect your maps are off, not your GPS. https://en.wikipedia.org/wiki/World_Geodetic_System https://en.wikipedia.org/wiki/World_Geodetic_System