New Jersey, which has declared a state of emergency, was the first to announce mandatory evacuations. The state's barrier islands from Sandy Hook south to Cape May must be cleared out by Sunday afternoon, along with Atlantic City's casinos.
"We have to prepare for the worst here," Gov. Chris Christie said.
Tolls will be suspended on the northbound Garden State Parkway and the westbound Atlantic City Expressway starting Sunday at 6 a.m. so people in those areas can leave more quickly, he said.
Gov. Tom Corbett declared a statewide disaster emergency ahead of the storm, which is expected to bring heavy rain to much of the state starting Sunday night, the governor's office said.
Flooding, power outages, and sustained high winds are all expected from the storm, his office said. Sandy could even bring snow to some areas in southwestern Pennsylvania and in higher elevations.
Gov. Jack Markell declared a state of emergency Saturday as Sandy forecast to hit the state within days. The state of emergency is a "limited" one, however, because it doesn't order driving bans or business closures.
Markell ordered the evacuation of all coastal communities and a flood-prone area in southern Delaware by Sunday night.
Shelters will be open beginning Sunday afternoon, Markell said.
To help prevent flooding, Markell says residents should clear storm drains and sweep up any leaves so that they won't clog drains.
Like several neighboring states, portions of Maryland could see as much as a foot of rain, according to the CNN Weather Unit -- a major reason the state has declared a state of emergency.
Besides flooding, strong winds are expected to cause significant power outages. The Baltimore Gas and Electric Company, for instance, says several hundred thousand customers could be affected, as early as Sunday.
In the coastal city of Annapolis, city crews distributed sandbags to residents and businesses to help them prepare for flooding.
DISTRICT OF COLUMBIA
The district is under a state of emergency, and local officials are working through the weekend to prepare residents, businesses, and infrastructure for the hurricane.
"The district is preparing in earnest" for the storm's effects, which could include heavy rain, street flooding, strong winds, power outages, and storm-surge flooding along the Potomac River and its tributaries, Mayor Vincent Gray said.
The local government distributed sandbags to residents and businesses Saturday at RFK stadium. Authorities have generators ready at major intersections in case traffic lights are knocked out, Gray's office said.
Sandbags were piled up inside restaurants in the Old Town section of Alexandria, along the banks of the Potomac River, in anticipation of Sandy's arrival.
The Virginia National Guard was authorized to bring as many as 500 personnel onto active duty.
Virginia was one of several states to declare a state of emergency ahead of the storm. Computer models predict parts of the state could see as much as a foot of rain, according to the CNN Weather Unit.
As a precaution, officials in Norfolk announced they would close on Sunday the Midtown Tunnel that spans the Elizabeth River, connecting the city with neighboring Portsmouth.
The storm has already forced the cancellation of rallies for both presidential campaigns. Vice President Joe Biden nixed a planned Saturday visit to Virginia Beach and Republican nominee Mitt Romney called off a planned Sunday rally in the same city.