along the top of the program there're 3 satellite buttons. one is landsat 7 or something, the next is pseudo 7 and the next is usgs. use the usgs one when zooming in on anything in the usa.

here's an example of a beach that's about 1/2 an hour from here just on the other side of the us border. the white is canada - where the usgs images are cut off.

(you can zoom in a lot farther on individual buildings etc, but it gets pixelated after a certain point)