This particular tree doesn't have the beautiful fall-color leaves that a Nuttall Oak provides. The leaves just go from green to brown. For that reason, I'm thinking it's something else. Thanks for your input. Much appreciated.

tree color can be very regional.. where are you.. big city name...

ken

Northeast Houston

Yes, acorn is too large for pin oak. In TX, Shumard oak is a possibility as their leaves are quite variable and acorn is larger than most other black/red oaks. Nuttall is possible even if leaves don't color well -- some individual trees just don't display the usual pattern. Also Nuttall has a relatively large acorn -- below.

In addition to autumn color for entire oak species not being exactly the same from one individual tree to another there are hybrids and intermediates between species out there in the world. So randomly encountered oaks may not fit descriptions of pure species. Otherwise characters of acorn cups (not shown in your picture) are one of the main things used to identify oaks.

Quercus texana in Flora of North America @ efloras.org

Illustration: Quercus texana (efloras.org)

Quercus Sect. Lobatae in Flora of North America @ efloras.org