St. Johns River bridges are listed in geographic order, moving east to west to Jacksonville, then north to south from Jacksonville to Lake Monroe

Dames Point Bridge—crosses the St. Johns west of flashing daybeacon #45
30 23.094 North/081 33.424 West
Fixed
169 feet of vertical clearance

Matthews Point Bridge—crosses the St. Johns south of flashing buoy #78
30 19.047 North/081 37.739 West
Fixed
152 feet of vertical clearance

Hart-Commodore Point Bridge—crosses the St. Johns west of flashing buoy #79
30 18.933 North/081 37.640 West
Fixed
135 feet of vertical clearance

Main Street Bridge—crosses the St. Johns near downtown Jacksonville, west of lighted nun buoy #82
30 19.345 North/081 39.514 West
Lift bridge
40 feet closed vertical clearance
Restricted opening
VHF Hailing Channel 9
Does not open at all Monday through Friday (except Federal holidays) from 7:00 a.m. to 8:30 a.m. and 4:30 p.m. to 6:00 p.m.—opens on demand at all other times

Hi, I am a Bridge Tender at Main Street bridge. The restricted hours are Monday – Friday 7-8:30am and 4:30-6pm(except Fed holidays). There are no restrictions on Saturday. Also, buoy #82 is now a lighted combination buoy (flashing 4 seconds red). Smooth sailing to all !
Dave

Every opening clearance is about 82ft. at Mean High Water (MHW) contrary to NOAA chart 11491 and Coast Pilot. Range of Tide is only about 18 inches. We can give up to 138ft. of clearance if needed with a special slow Highlift procedure.
Dave (Bridge Tender at Main Street Bridge)

Acosta Bridge—crosses the St. Johns in downtown Jacksonville hard by charted Hendricks Point
30 19.372 North/081 39.889 West
Fixed
75 feet of vertical clearance

Florida East Coast Railway Bridge—crosses the St. Johns immediately west of the Acosta Bridge
30 19.355 North/081 39.928 West
Bascule
5 feet closed vertical clearance
Usually open unless a train is due—delays before, during, and after a train passes can be lengthy

Note temporary closure schedule in a recent Local Notice to Mariners:
http://cruisersnet.net/fec-rr-bridge-closures-mile-24-9-of-st-johns-river-jacksonville-fl/

Fuller Warren/I-95 Bridge—crosses the St. Johns River in downtown Jacksonville near the charted location of San Marco
30 18.927 North/081 40.333 West
Fixed
65+ feet of vertical clearance

Three Mile/I-295 Bridge—crosses the St. Johns south of Beauclerc Bluff and unlighted daybeacon #9
30 11.394 North/081 40.038 West
Fixed
63 feet of vertical clearance (officially listed as 65 feet)

Shands/Green Cove Springs Bridge—crosses the St. Johns southeast of the village of Green Cove Springs and flashing daybeacon #20
29 58.927 North/081 37.367 West
Fixed
45 feet of vertical clearance
(sets the height limit for cruising the St. Johns south of Green Cove Springs)

Palatka/Highway 17 Bridge—crosses the St. Johns south of flashing daybeacon #48
29 38.754 North/081 37.363 West
Fixed
65 feet of vertical clearance

Buffalo Bluff Railway Bridge—crosses the St. Johns at Buffalo Bluff, near unlighted daybeacon #27
29 35.712 North/081 40.923 West
Bascule
7 feet closed vertical clearance
Usually open unless a train is due but it can be closed for up to 40 minutes both before and after a train’s passage

Astor Highway Bridge—crosses the St. Johns at the village of Astor, south of flashing daybeacon #28
29 10.046 North/081 31.385 West
Bascule
20 feet closed vertical clearance
Opens on demand
VHF Hailing Channel 9

De Land/Whitehair Bridge—crosses the St. Johns south of flashing daybeacon #39
29 00.524 North/081 22.923 West
Bascule
15 feet closed vertical clearance
Opens on demand
VHF Hailing Channel 9

Port of Sanford Railway Bridge—crosses the St. Johns immediately northwest of the juncture with Lake Monroe
28 50.272 North/081 19.477 West
Bascule
7 feet closed vertical clearance—usually open unless a train is due

Lake Monroe/Highway 17 Bridge—crosses the St. Johns immediately northwest of the juncture with Lake Monroe
28 50.263 North/081 19.455 West
Fixed
45 feet of vertical clearance

Lake Monroe/I-4 Bridge—crosses the St. Johns immediately northwest of the juncture with Lake Monroe
28 50.137 North/081 19.150 West
Fixed
45 feet of vertical clearance