Former Arizona Rep. Gabrielle Giffords and her husband, retired Astronaut Mark Kelly, are moving back to Tucson on Sunday, a big milestone in the former Democratic congresswoman's recovery.

Kelly announced the news on Twitter Sunday morning:

Giffords has lived in Houston, Texas, since Jan. 21, 2011, after she survived being shot by Jared Lee Loughner in Tucson on Jan. 8 of that year.

She was released from a Houston hospital that June, and visited Tucson not long after -- the first of a number of visits to her home district. But the couple continued living at Kelly's home in Houston, where he was based at the Johnson Space Center.

Giffords has been increasingly active in recent months as her recovery has progressed, and her resignation from Congress in January hasn't kept her from making public appearances or political endorsements.

She appeared at June event in Tucson in support of Ron Barber, her former aide, who successfully won Giffords' House seat in a June special election. And last month, Giffords and Kelly visited the French Alps.

Six were killed in the January, 2011, shooting, and 13 others were injured, including Giffords and Barber. On Tuesday, Loughner pleaded guilty and will be sentenced to life in prison.

Earlier on HuffPost:

Loading Slideshow...
  • Open Your Eyes (Snow Patrol)

    <a href="http://www.huffingtonpost.com/2011/01/12/obama-gabrielle-giffords-opens-eyes_n_808346.html" target="_hplink"><strong>(Jan. 8, 2011) --</strong></a> Four days after <a href="http://www.huffingtonpost.com/2011/01/08/gabrielle-giffords-shot-c_n_806211.html" target="_hplink">Rep. Gabrielle Giffords (D-Ariz.)</a> was wounded in a grisly shooting, President Barack Obama informed memorial service members that she opened her eyes for the first time. "I can tell you this," Obama said. "She knows we're here and she knows we love her and she knows that we will be rooting for her throughout what will be a difficult journey." (AP Photo/Chris Carlson)

  • Stand (Rascal Flatts)

    <strong><a href="http://www.huffingtonpost.com/2011/01/19/gabrielle-giffords-stands-on-two-feet_n_811355.html" target="_hplink">(Jan. 19, 2011) --</a></strong> Outside the University of Arizona's Medical Center, a decorated paper plate offered well wishes for the Tucson shooting victims. With assistance from doctors, Giffords stood on her own two feet for the first time since the incident. The congresswoman was soon transferred to TIRR Memorial Hermann Rehabilitation Hospital in Houston, one of the top-rated rehab facilities in the country. (AP Photo/Susan Montoya Bryan)

  • Stand By Me (Ben E. King)

    <strong><a href="http://www.huffingtonpost.com/2011/05/16/gabrielle-giffords-shuttle-launch_n_862400.html" target="_hplink">(May 16, 2011) --</a></strong> In this Feb. 2011 file photo, Giffords' husband Mark Kelly held a wrist band decorated with a peace sign, heart and the word 'Gabby'. By mid-May, Giffords was watching Kelly fly off into space on NASA's Endeavour expedition. The couple exchanged their wedding rings before takeoff. (Photo by Eric Kayne/Getty Images)

  • Fighter (Christina Aguilera)

    <a href="http://www.huffingtonpost.com/2011/06/28/gabrielle-giffords-public-appearance_n_885772.html" target="_hplink"><strong>(June 28, 2011) --</strong></a> Giffords made her first public appearance since being wounded in the Jan. 2011 shooting, attending a ceremony at Texas' Space Center Houston with Kelly. She received a standing ovation from the crowd. (AP Photo/southwestphotobank.com, P.K. Weis)

  • You're The Inspiration (Chicago)

    <a href="http://www.huffingtonpost.com/2011/08/01/gabrielle-giffords-debt-ceiling-vote_n_915569.html" target="_hplink"><strong>(Aug. 1, 2011) --</strong></a> Giffords completed her first House floor appearance since the shooting, attending a vote on the debt ceiling. "The reaction in the chamber was the most enthusiastic, exuberant, exhilarating -- I mean we were all crying -- thrilled -- you know, we just knew she would make a triumphant return," Rep. Debbie Wasserman Schultz (D-Fla.) said. (AP Photo/House Television)

  • Don't Stop (Fleetwood Mac)

    <a href="http://www.huffingtonpost.com/2011/08/30/gabrielle-giffords-walking-writing_n_941894.html" target="_hplink"><strong>(Aug. 30, 2011) --</strong></a> Via a Giffords spokesperson, the Associated Press learned that less than eight months after being wounded, the congresswoman was walking and writing on her own. (Photo by P.K. Weis/Giffords Campaign via Getty Images)

  • I Didn't Know My Own Strength (Whitney Houston)

    <a href="http://www.huffingtonpost.com/2011/11/10/gabrielle-giffords-tv-interview_n_1087420.html" target="_hplink"><strong>(Nov. 10, 2011) --</strong></a> Giffords' first TV interview since the shooting went to ABC News. The congresswoman answered questions with a clear voice, telling host Diane Sawyer that she felt "pretty good." Giffords added that the recovery had been "difficult."

  • It's So Hard To Say Goodbye To Yesterday (Boyz II Men)

    <a href="http://www.huffingtonpost.com/2012/01/22/gabrielle-giffords-stepping-down_n_1222168.html" target="_hplink"><strong>(Jan. 22, 2012) --</strong></a> A little more than a year after the shooting, Giffords announced that she was leaving Congress. In a Facebook video, she cited her recovery as a primary concern, thanking her constituents for their support: "I don't remember much from that horrible day, but I will never forget the trust you placed in me to be your voice," Giffords said. (AP Photo/Office of Gabrielle Giffords)

  • I Can See Clearly Now (Johnny Nash)

    <a href="http://www.huffingtonpost.com/2012/01/24/gabrielle-giffords-last-bill_n_1229309.html" target="_hplink"><strong>(Jan. 24, 2012) --</strong></a> Two days before exiting Congress, Giffords unveiled her final bill, aimed at stopping cross-border drug smugglers. "Congresswoman Giffords is committed to taking this crucial step that would help secure the border against drug smugglers," Giffords' chief of staff, Pia Carusone, said in a statement. "That's why she decided this would be the last bill she introduces before she steps down." (Photo by Jonathan Gibby/Getty Images)

  • Hero (Mariah Carey)

    <a href="http://www.huffingtonpost.com/2012/01/25/gabrielle-giffords-state-of-the-union-appearance_n_1230480.html" target="_hplink"><strong>(Jan. 24, 2012) --</strong></a> Giffords made a moving appearance at Obama's 2012 State of the Union address. Her presence drew rousing applause, inspiring colleagues on both sides of the aisle. (Photo by Saul Loeb-Pool/Getty Images)