# Florida State Road 688

State Road 688 (SR 688) is an east–west route in Pinellas County running from Indian Rocks Beach to northeastern St. Petersburg, Florida, where it merges onto Interstate 275 (I-275).

## Route description

The highway changes its name as it heads east across Pinellas County. From Gulf Boulevard in Indian Rocks Beach, it runs along 5th Avenue and crosses the bridge over the Intracoastal Waterway as the Indian Rocks Causeway. Once off the causeway, it becomes Walsingham Road and runs on to the intersection of Walsingham and Ulmerton Roads. Walsingham continues east, but State Road 688 loops north and then east on Ulmerton Road. It skirts Largo before crossing U.S. Route 19 (US 19) and then merges briefly with Roosevelt Boulevard (SR 686). It continues into northeast St. Petersburg and its traffic merges with I-275.

## History

Ulmerton Road was named for the community of Ulmers, which arose around Marion Ulmer's turpentine still, timber and naval stores interests in the first half of the twentieth century. In the 1950s, the area was very rural, and cattle were driven along the then dirt road. Today it carries traffic across the middle of the most densely populated county in Florida.

## Major intersections

The entire route is in Pinellas County.
| Location | mi | km | Destinations | Notes |
| Indian Rocks Beach | 0.000 | 0.000 | SR 699 south / CR 183 north (Gulf Boulevard) – Indian Shores, Belleair Shore | |
| Indian Rocks Beach Largo | 0.283– 0.370 | 0.455– 0.595 | Indian Rocks Causeway over The Narrows (Gulf Intracoastal Waterway) | Indian Rocks Causeway over The Narrows (Gulf Intracoastal Waterway) |
| Largo | 0.693 | 1.115 | Hamlin Boulevard (CR 213 south) | |
| Largo | 1.192 | 1.918 | CR 233 (Indian Rocks Road / Oakhurst Road) – Belleair Bluffs, Seminole | |
| Largo | 1.948 | 3.135 | Vonn Road / 131st Street (CR 263) | |
| ​ | 2.250 | 3.621 | Walsingham Road (CR 330 east) - Botanical Gardens, Heritage Village, Museum of Art | |
| Largo | 3.914 | 6.299 | Ridge Road (CR 313 south) | |
| Largo | 4.035 | 6.494 | CR 321 (Ridge Road / 113th Street) | |
| Largo | 4.545 | 7.314 | US 19 Alt. (Seminole Boulevard / SR 595) – Largo, Seminole | |
| ​ | 5.541 | 8.917 | Lake Avenue Southeast (CR 375 north) | |
| Largo | 6.053 | 9.741 | CR 1 (Starkey Road) | |
| Largo | 7.072 | 11.381 | Belcher Road (CR 501) | |
| Largo | 8.114 | 13.058 | SR 693 (66th Street) – Clearwater, Pinellas Park | |
| ​ | 8.457– 8.546 | 13.610– 13.753 | US 19 (SR 55) – Clearwater, Pinellas Park, St. Petersburg | |
| ​ | 8.604 | 13.847 | 62nd Street North (CR 563) | |
| Pinellas Park | 9.851 | 15.854 | 49th Street North (CR 611) | |
| Pinellas Park | 10.325– 10.403 | 16.616– 16.742 | SR 686 west (Roosevelt Boulevard) – Largo, Clearwater | West end of SR 686 overlap; no access from SR 688 east to SR 686 west |
| St. Petersburg | 11.137– 11.570 | 17.923– 18.620 | SR 686 east (Roosevelt Boulevard) to I-275 south – St. Petersburg | Interchange; east end of SR 686 overlap |
| St. Petersburg | 12.913 | 20.781 | I-275 (SR 93) / Martin Luther King Jr. Street (CR 803 south) – Tampa, Bradenton | I-275 exit 31; no access from I-275 north or CR 803 north to SR 688 west |
| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi Concurrency terminus |||||