Maine became the latest state to institute requirements for domestic travelers Friday when its governor issued an executive order requiring travelers to the state to self-quarantine for 14 days to lessen the chance of transmitting the coronavirus.

In the absence of federal domestic travel restrictions to stem the spread of COVID-19, the governors of at least 40 states have stepped in, issuing stay-at-home orders. And more than a dozen are discouraging interstate travel by announcing quarantine requirements for travelers or people who live there traveling home from other states. 

Alaska, Florida and Hawaii were the first states to institute state-to-state quarantine requirements for travelers last week, and about a dozen other states have followed suit.  

The U.S. Centers for Disease Control and Prevention issued a travel advisory on March 28 urging residents of New York, New Jersey and Connecticut to curtail nonessential travel in order to help limit the spread of the coronavirus from the area that has become the epicenter of the U.S. outbreak. The agency noted on its website that it "does not generally issue advisories or restrictions for travel within the United States."

Legal experts have said President Donald Trump doesn’t have the authority to impose a national lockdown as the heads of countries such as Italy, Spain, France and Britain have done. 

Here's a breakdown of the states that have instituted quarantine orders for travelers. 

Alaska

In Alaska, travelers arriving at state airports will be required to fill out a mandatory State of Alaska Travel Declaration Form and identify their "designated quarantine location," which would be home for residents and a hotel room or rented lodging for visitors. 

The state's order requires travelers to go straight to their quarantine location from the airport and remain there for 14 days, or for the duration of their stay if it's shorter. 

On March 28, Gov. Mike Dunleavy expanded Alaska's stay-at-home order to travel within the state. Only workers who support critical infrastructure are exempted.

Delaware

Delaware Gov. John Carney is ordering all out-of-state travelers to self-quarantine for 14 days. It also applies to anyone who entered Delaware in the 14 days prior to March 30 but does not apply to travelers passing through the state. 

The state of emergency modification authorizes Delaware law enforcement officers to stop vehicles with out-of-state plates.

Florida

Florida's executive order requires people arriving on flights from the New York tri-state area – New York, New Jersey and Connecticut – to quarantine for 14 days or for the length of their visit if that time is shorter. The mandates make exceptions for airline employees, military, health and emergency personnel.

Gov. Rick DeSantis has issued a separate separate order directing people driving in from Louisiana to self-quarantine, too. Highway checkpoints have been set up. 

Hawaii

Hawaii Gov. David Y. Ige's emergency proclamation mandates all visitors and residents arriving at airports in the state to self-quarantine for 14 days. A supplementary proclamation requires all residents and visitors traveling between any of the islands to do the same. 

According to the state, travelers will be required to complete a Department of Agriculture Plants and Animals Declaration Form on their flight and present it to checkpoint staff after landing. The travelers must then go straight to the "designated quarantine location" that they identify on the form and remain there for 14 days or the length of their stay if it is shorter. 

Kansas

State health officials said residents who traveled to California, Florida, New York, Washington on or after March 15; Illinois or New Jersey on or after March 23; or Colorado and Louisiana on or after March 27 must self-quarantine for 14 days after returning to Kansas.

Kentucky

Kentucky Gov. Andy Beshear's executive order directs residents not to travel to other states, with exceptions to go to work, shop for essential supplies, receive medical attention care for a minor, elderly or disabled person or when required by court order. Residents returning from another state must self-quarantine for 14 days. 

Maine

Maine's executive order requires travelers to the state to self-quarantine for 14 days, regardless of their state of residency. The order also calls on visitors not to come to the state if they are experiencing symptoms of COVID-19.

Massachusetts

All travelers to Massachusetts are instructed to self-quarantine for 14 days, and visitors are urged not to travel to Massachusetts if they have coronavirus symptoms. Health care, public health, public safety, transportation and designated essential workers are exempt.

Montana

Gov. Steve Bullock directed non-work-related travelers arriving from another state or country to self-quarantine for 14 days. He also directed the Montana Department of Commerce to "advise vacation listing and rental sites that they must notify potential out-of-state renters about the quarantine requirement," according to a news release on his website. 

The Montana National Guard has also been authorized to check travelers' temperatures at airports and rail stations. 

Nevada

Gov. Steve Sisolak  issued a travel advisory urging all Nevada residents and visitors to self-quarantine for 14 days after arriving or returning. The advisory does not apply to health care, public health, public safety, transportation and food supply essential employees.

North Dakota

The North Dakota Department of Health issued a confinement order for people arriving to the state from abroad or 23 states to self-quarantine for 14 days, according to a questionnaire on the agency's website. The department recommends snowbirds and spring breakers also self-quarantine, according to KFGO and KVRR. 

Oklahoma

Gov. Kevin Stitt's executive order requires people arriving on flights from the New York tri-state area (New York, New Jersey and Connecticut), Washington state, California or Louisiana to quarantine for 14 days. Airline personnel, military, health care and emergency workers are exempt. 

Rhode Island

Rhode Island's executive order requires a 14-day self-quarantine for any person traveling in from any other state. It does not apply to public health, public safety or health care workers. The previous order that singled out those coming from New York was repealed after Rhode Island authorities were criticized for stopping cars with New York license plates and going door-to-door searching for New York travelers.

South Carolina

South Carolina's executive order requires people who enter the state from New York, New Jersey, Connecticut or New Orleans to self-quarantine for 14 days. Airline and military personnel, health care workers and emergency responders are exempt. 

Texas

Gov. Greg Abbott ordered travelers arriving from New York, New Jersey, Connecticut or New Orleans to self-quarantine for 14 days. He later added California, Louisiana, Washington state, Atlanta, Chicago, Detroitand Miami. Highway checkpoints are set up to collect a form from Louisiana drivers at the states' shared border. Military personnel are exempt along with health care, emergency or critical-infrastructure workers. 

Vermont

Vermont's executive order requires anyone, resident or not, traveling into Vermont "for anything other than an essential purpose" to self-quarantine for 14 days. Essential purposes include personal safety: grocery shopping, giving or receiving medical care and for work. The governor advised anyone who has COVID-19 symptoms from coming to Vermont, along with people from the following states and cities: New York, New Jersey, Connecticut, Florida, Louisiana, Detroit and Chicago.

West Virginia

West Virginia's executive order requires anyone traveling from New York, New Jersey, Louisiana, Italy or China to isolate for 14 days. Exemptions are made for people who commute into or out of the state for work, military personnel and emergency and health care workers. 

Contributing: Nicquel Terry Ellis, Jorge L. Ortiz, USA TODAY; Jon Campbell, New York State Team - USA TODAY Network; Reno Gazette Journal; The Associated Press