Just poking around:
tshaonline.org/handb ook/online/articles/ hcm17
in part:
The area that now comprises Montgomery County has long been the site of human habitation. Numerous artifacts from the Paleo-Indian (10,000–6,000 B.C.) and Archaic (6,000–200 B.C.) cultures have been found in the area, suggesting that it has been continuously occupied for more than 10,000 years. When the first Europeans arrived the region it was dominated by various tribes of the Atakapan Indians, a predominantly hunting and gathering people whose range extended south and eastward to the Gulf Coast. In the early eighteenth century one of these tribes, the Arkokisas (Orcoquisacs) had campsites along Peach Creek and on the banks of the San Jacinto River. The Bidai Indians, another Atakapan tribe, also ranged across most of the future county, their territory extending as far north as the Old San Antonio Road. Most of these natives peoples eventually succumbed to European diseases, were killed by other Indian tribes, intermarried, or migrated elsewhere; by 1850 virtually no trace of them remained.