At town meeting in 2009, Bath voters approved $2.92 million for the project.
The federal share of the project, coming from the Federal Highway Administration National Historic Covered Bridge Preservation Program, is the largest, at $2.32 million.
The state, from the New Hampshire Department of Transportation's Municipally Managed Bridge Aid Program, will kick in $464,000, leaving the town share at just $136,000.
The actual construction fees are estimated at $2.491 million, said town administrative assistant Pam Murphy.
That excludes the cost of the preliminary engineering that has been ongoing since 2009.
Wright Construction Co. Inc, of Mt. Holly, Vt., the contractor for the work on the Haverhill-Bath Bridge, which, according to state transportation records is the oldest covered bridge in New Hampshire, will do the work on the Bath Bridge.
Hoyle, Tanner and Associates also did the design for the 1998 repairs to the Swiftwater Bridge, the construction of which was also carried out by Wright Construction.
The last repairs of significance to the Bath Bridge were in 1987 or 1988, said James.
"It's been closed a couple of times for repairs and was closed a few years ago when ice jammed and damaged it," said Murphy.
The existing Bath Bridge, built in 1832 at a cost of $2,900, is the fifth bridge to stand on the site and is listed on the National Register of Historic Places.
The original Bath Bridge was built in 1794 at a cost of $366.66, according to a town history. That bridge was destroyed by a flood and replaced in 1806.
The waters continued to wreak havoc, however, and the second and third bridges were also destroyed by floods and replaced in 1820 and 1824.
It was a fire, in late 1830, that took out the fourth bridge.
When the fifth Bath Bridge was constructed, it had hewn arches. New overlapping arches were added in 1920, when the bridge was raised over the railroad bed.
According to the historical narrative, "At one time, there was a sign posted at the bridge which prohibited riding horses across the bridge at a trot. It was believed that the impact of trotting horses could cause the structure to fall apart."
The Bath Bridge, at 374Â½ feet long and 24Â½ feet wide, is a burr truss style bridge with supplemental arches.
"It's been there since 1832 without a lot of work," said James.
Because of the scope of the work, the rehabilitation cannot be done in phases with intermittent traffic openings, he said.
"We realize it's an inconvenience while it's closed and we certainly appreciate people's patience," said James.
Because the Bath Bridge is historic, the federal Section 106 review process requires a thorough review before any work can begin.
"We feel very lucky to be involved in it," said James.