The Red Cross and other organizations are hosting Christmas card drives for troops overseas. Reuters

They spend the holiday season away from their families, often in dangerous and uncomfortable conditions. Now, charities and school groups across the country are trying to give back to U.S. military members by sending Christmas cards to soldiers overseas. The annual holiday drives are designed to cheer up troops unable to come home in December.

The Red Cross' Holiday Mail for Heroes campaign, one of the more popular programs, allows anyone to send holiday greetings to military members and veterans through Dec. 5. Events featuring card decorating and signings are held in communities across the nation, with local Red Cross offices sending the completed cards to military associations and bases. To make sure the cards arrive on them, they have to be completed before the deadline and delivered to a local Red Cross office. Glitter is not allowed, and monetary donations are also prohibited.

For those looking for an easier approach, military supporters can share seasonal messages with troops by using the hashtag #HolidayMail on Facebook, Twitter and social media networks. “Getting people to sign holiday cards for veterans and soldiers is a great way to spread the spirit of the holidays,” Dena Howard, director of service to armed forces for the Red Cross, told the Omaha World-Herald. “The look on the soldiers’ and veterans’ faces when they get the cards really makes it all worth it."

The U.S. Military allows family, friends and corporations to send care packages to servicemembers during the holidays. Participating non-profits organizations are listed here.

Local charities and schools are also hosting Christmas card drives for troops. In Kentucky, the Owensboro-Daviess County Convention & Visitors Bureau recently kicked off its eighth annual Christmas Cards for Veterans drive. "It's become a tradition for some families," said Beck Glenn, the CVB's marketing coordinator.

At one Texas middle school, students recently penned more than 800 handmade cards for service members and veterans. Students at Copperas Cove Junior High School wrote the Christmas cards for an Air Force squadron in Iraq, said Terri L. Jones, the school's military student transition consultant.

“It’s nice to give back to people who are doing something nice for you,” said Condre Ross, 15. His card included a Liberty Bell symbol, reported the Cove Herald.

In Missouri, Little Patroits Embraced organizes an annual toy drive for children of servicemembers through Nov. 30. New, unwrapped toys are accepted.

Operation Homefront also distributes Christmas gifts and hosts events for military members. This year, they will host events in New York and Massachusetts.

You don't have to wait until the holiday season to show support for the military. The USO allowes anyone to send a thank you message to servicemembers throughout the year. Other organizations also send correspondence to soldiers year-round.

The U.S. military has roughly 200,000 troops stationed in 144 countries and territories, with another 20,000 sailors and Marines deployed on Navy ships.