On the left side of the Park Finder map viewer, there are navigation controls. These tools appear as white buttons.
There are + and – buttons to zoom in to and out from the center of the map. The button in the middle, that looks like a house, is the Default extent button. Clicking the Default extent button will return you to the inital extent of the map, when it is first loaded.
Other ways to zoom in and out of the map are as follows. Hold down the shift key and drag a box on the map, to zoom in. Hold down Ctrl+Shift to zoom out. Or roll your mouse roller to zoom in and out.
To pan around the map, simply click on the map then drag the map to a new position. The farthest the map will zoom out is a scale of 1:480,000 and the farthest the map will zoom in is 1:600.