Our physical address is:

ATP Oil & Gas Corporation
4600 Post Oak Place
Suite 200
Houston, Texas  77027-9726

We are located on the west side of Houston, just inside Loop 610, and between Highway 59 and Interstate 10, north of the Galleria shopping center.

Once you get on Loop 610, exit at San Felipe, and turn east.
The first street on the north side of San Felipe is Post Oak Park Drive.
Turn there and go to the second stop sign.
Our office is on the northeast corner of Post Oak Place Drive and Post Oak Park Drive, although on the map below from MapQuest actually looks as if it is further down the street than that.