| Official Name: | Port Alto, Texas |
| Settlement Type: | Unincorporated community |
| Pushpin Map: | Texas#USA |
| Pushpin Label: | Port Alto |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Texas |
| Subdivision Type2: | County |
| Subdivision Name2: | Calhoun |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation Ft: | 10 |
| Coordinates: | 28.66°N -96.4133°W |
| Area Code: | 361 |
| Blank Name: | GNIS feature ID |
| Blank Info: | 1365594 |
Port Alto is an unincorporated community in Calhoun County, Texas, United States. According to the Handbook of Texas, the community had a population of 45 in 2000. It is part of the Victoria, Texas Metropolitan Statistical Area.
Port Alto is located at the intersection of Texas State Highway Spur 159 and Farm to Market Road 307 on the western shore of Carancahua Bay, 4miles east of Olivia, 22miles southwest of Palacios, and 21miles northwest of Port Lavaca in northeastern Calhoun County.[1]
Port Alto is served by the Calhoun County Independent School District.