Before the days of the interstates, US Route 1 was the main highway for the eastern half of the US. Replaced by Interstate 95, route 1 is now used primarly for short distance travel by locals. Littered with aging motels and odd roadside souvenir stands. Strange edfices that are anachronisms in a modern world, proudly proclaming on heterogeneously painted signs: "Color TV".

It is still possible to follow US 1 from Key West to Fort Kent, Maine, with only minimal detours onto I-95 and other interstates (US 1 does not parallel I-95 from Jacksonville FL to Petersburg VA). US 1 is still the main road south of Miami to Key West, since I-95 ends there and Florida's Turnpike ends just a bit to the south in Florida City. US 1 is also the main road north of Houlton, Maine, but that is a fairly local road (most thru traffic will use Trans-Canada Highway 2 on the other side of the border).

Florida: South of Miami, as I said above, US 1 is still the main route. North of there it is mostly a four-lane route that passes thru the main coastal towns, roughly following the old Dixie Highway (east leg). It however does not go along the coast; that honor is reserved for A1A. The route was four-laned before the Interstates, and continues to serve local and semi-local traffic, including commuter traffic in the urban/suburban areas. US 1 splits from I-95 in Jacksonville. There are no multiplexes with Interstates; most maps show one with I-95 in southern Jacksonville, but it actually uses Old Kings Hwy. In addition, I-95 ends/begins at US 1 in south Miami; going northbound this is signed as a split. There are a couple short freeway sections in Jacksonville on the Main St Bridge and 20th St Expwy.
Signage is typical Florida; excellent signage in rural and suburban areas, and reasonably easy to follow in urban areas.
An alternate route exists in Jacksonville; this would more accurately be signed as a bypass route, since it is almost all freeway. A business route exists in Saint Augustine on the old route.

Georgia: US 1 stays away from I-95, instead taking a more inland route. It is almost all rural, popping into Augusta as it crosses into South Carolina. Some portions are four lane, but most of it is two lane.
Business routes exist in Waycross, Swainsboro, Wadley, and Louisville. They are probably all the old route.

South Carolina: US 1 follows the I-20 corridor through most of South Carolina, splitting north of Columbia in Camden. Most is rural two lane, with some reasonably sized cities and Columbia along the way.

North Carolina: US 1 begins as a two lane rural route, but becomes a rural freeway from Sanford to Raleigh. It bypasses Raleigh on I-440 and is a four lane road to Henderson, where the freeway merges with I-85 and US 1 leaves onto the old two lane.
There are alternate routes in Youngsville and Franklinton, both part of the old route. Business routes exist in Sanford and Henderson, probably both old routes.

Virginia: US 1 continues to parallel I-85 to its end at Petersburg, and then parallels I-95 through Richmond and Fredericksburg to Northern Virginia, where it becomes a major suburban arterial (Jefferson Davis Hwy). There is a short almost-freeway at Washington National Airport and it then joins with I-395 over the 14th St Bridge into Washington, DC.
Fredericksburg has a business route, probably on the old route.

Washington, DC: US 1 quickly leaves I-395 and runs roughly east-west thru the city. Signage is fairly bad, but all turns are likely marked.
There is an alternate route in the northern/eastern half; it leaves the city into Maryland.

Maryland: US 1 runs from Washington to Baltimore on the Baltimore-Washington Boulevard, once the main road. It passes thru Baltimore, bypassing the city center, and continues roughly parallel to I-95, but a bit more inland, into Pennsylvania.
The alternate route in Washington, DC continues into Maryland for a bit. In addition, there is in alternate route in Baltimore going a bit closer to downtown than the main route. The old route in Bel Air and Hickory are business routes.

Pennsylvania: US 1 quickly becomes a freeway, bypassing the small towns on the old road. At Kennett Square, the freeway gives way to a four lane surface road to Media, where there is a short freeway bypass and then a surface stretch on City Ave along the Philadelphia city line. US 1 multiplexes with I-76 for one exit and then leaves onto the Roosevelt Expwy. This becomes Roosevelt Blvd shortly, a twelve lane arterial in a 3-3-3-3 configuration. Left turns are made from the inner lanes and right turns from the outer lanes. This continues to the city line, where it becomes a divided highway and shortly a freeway. The freeway crosses the bridge into Trenton. Signage in Pennsylvania is generally good, but few turns are made.
The old route in Fairless Hills is now a business route.

New Jersey: US 1 enters New Jersey as the Trenton Freeway, thru downtown Trenton. This freeway was part of the original plan for I-95, but I-95 now bypasses Trenton to the north, and will soon bypass to the south. North of Trenton, US 1 becomes a 4 to 6 lane arterial with jughandles, New Jersey's answer to left turn lanes. This continues, with less interchanges and more jughandles as you continue north, to New Brunswick. From there to Rahway, interchanges pick up in intensity but jughandles continue. US 9 joins on in Woodbridge and forms the famous US 1-9. North of Rahway, NJDOT didn't even bother with jughandles; left turn lanes are very common. Just north of Elizabeth, US 1 undergoes another transformation, into an eight lane freeway with local and express lanes. This goes past the massive interchange complex at Newark Airport, and heads north on twin viaducts, the southbound one built in 1928 (and recently renovated), into the Pulaski Skyway. The Pulaski Skyway, the "big black brontosaurus", rises above the industrial landscape of northern New Jersey on a four lane viaduct built in 1933. Lanes are narrow and ramps are on the left, so trucks are banned to parallel surface route US 1-9 truck, the old pre-skyway route. US 1 exits the Skyway at Tonnele Circle, while NJ 139 (former US 1-9 business) continues towards the Holland Tunnel and New York City. US 1-9 goes north on Tonnele Ave, a four lane route with jughandles. At NJ 3, the jughandles end and the route has the look of a standard old suburban arterial. It joins on the US 46 semi-freeway east, and enters the George Washington Bridge (along with I-95, US 9, and half of US 46). Signage in New Jersey is very good, since it is a major route. It however makes few turns.
There is a business route in North Trenton on the old route. Signage extends it thru downtown into Pennsylvania, but there is no signage there and it does not officially do that. Truck US 1-9 is the old route in Newark and Jersey City, since trucks are not allowed on the Pulaski Skyway.

New York: US 1 spends its whole distance in New York in the city and suburbs. It starts out on the Cross-Bronx Expwy (I-95), and splits at Fordham Rd. It travels thru the Bronx and then parallels I-95 in the suburbs. Signage isn't bad.

Connecticut: US 1 parallels the coast, usually closer than I-95. It passes thru all the cities, and is mostly two lanes outside. In many places it is signed east-west; it is signage north-south on I-95 however.
The old route in Wequetequock and Stonington is now an alternate route.

Rhode Island: US 1 enters at Westerly. Soon it becomes a rural four lane route, and at Charlestown it becomes an almost freeway. There are no overpasses and occasional driveways, but left turns are all done by median U-turn ramps and there is no cross traffic at a single point. Around Wakefield it is a true freeway, and then it reverts to a rural four lane road with some jughandles. Soon RI 4 splits off as the main road (almost freeway) and US 1 continues as a two lane road. At Wickford RI 1A joins and it becomes four lanes to East Greenwich, where it is once again two lanes. The four lanes start again as it nears Providence, and it passes thru Providence and Pawtucket on its way to Massachusetts.
US 1A (functionally an alternate) goes east of US 1 thru the Providence area. It enters Massachusetts as MA 1A. There are also several sections of RI SCENIC 1A further south, and a short business/bypass split in Warwick.
US 1 takes the more coastal route, while I-95 takes the direct route. Even in the 1920s, NE 1A (later RI 1A) followed roughly the path of I-95. In 1947, Connecticut tried to reroute US 1 along CT 184 and RI 3, which parallels I-95. Little Rhodey refused, and countered with a proposal for US 1A. This never happened.
Signage in Providence and Pawtucket is horrible. Almost no turns are signed, and no known map shows the correct path.

Massachusetts: South of the Boston area, uses the old four lane route parallel to I-95. At Route 128, it joins on and uses Route 128 (I-95 and I-93) and the Southeast Expwy to downtown. Until 1989, it used a surface alignment; many signs remain. North of downtown Boston, it leaves onto the Tobin Bridge and Northeast Expwy, once signed I-95 but never completed. In Revere, the freeway ends with ghost roadway going off thru the swampland. US 1 contineus as a four to six lane arterial with no traffic lights or cross traffic, except for one jughandle in the Route 128 interchange. At the second crossing of I-95, in Danvers, it becomes a two lane rural road into New Hampshire.
There are no alternates per se, but there are several MA 1As, one of which crosses the line onto US 1A in Rhode Island. These are all parts of the old route.
Signage is very good, although it rarely leaves the main road.

New Hampshire: US 1 follows the second-generation old main route (as it does in Massachusetts) parallel to I-95. Not much else to say.
The route along the shore (probably never the main route) is NH 1A. Portsmouth has a bypass along an almost freeway; it extends into Maine.

Maine: US 1 roughly parallels I-95, but goes much closer to the coast. A short freeway exists from Brunswick to Bath. US 1 crosses the dying I-95 in Houlton and ends in Fort Kent.
Alternates exist in York Corner-Cape Neddick, Portland, Rockland, Bangor (a long one along the former main route), Millbridge-Harrington, Jonesboro-Machias, and Mars Hill-Van Buren. They are probably all parts of the old route, except maybe the last. Damariscotta has a business route on the old route. The bypass in Portsmouth NH also extends into Maine.

Sources: http://www.us-highways.com/flausa.htm http://www.us-highways.com/flautotr.htm http://www.us-highways.com/usban.htm http://www.state.nj.us/transportation/framed/stright.htm http://www.kurumi.com/roads/ct/us1.html personal knowledge

A chain of United States roads, streets, and highways stretching along the East Coast of the United States, from Fort Kent, Maine, to Key West, Florida. It traverses all of the original 13 states, except Delaware.

In 1925, US 1 was numbered as such because parts of it follow the first true road connecting the 13 Colonies, the "Post Road".  Traffic on US 1 now follows I-95 mostly, but US 1 is quite free of interstate highways for long stretches, going through the center of some of the largest cities in the US.

Jct - Junction
C - Captured
F - Free
BP - Begin Peralleling
EP - End Paralleling
OWP - One-way pair

Maine

New Hampshire

Massachusetts

Rhode Island

Connecticut

New York

New Jersey

Pennsylvania

Maryland

District of Columbia

Virginia

North Carolina

South Carolina

Georgia

Florida


1Every map I can find shows US 1 following I-95 for a short section; however, SPUI's website directs it onto Kings Av and Prudential Dr instead.

AAA Road Atlas, 1994

http://www.futureboston.org/bostonmaps.htm

http://www.bigdig.com/thtml/mapframe.htm

Many thanks to SPUI for suggestions in Rhode Island and Florida, pointing me to the wonderful maps on his own website, as well as pointing me to http://www.usroute1.net/

Log in or registerto write something here or to contact authors.