A member of the Eglish club, she has served five years as vice-chair and succeeds Ciaran McLaughlin, who completed his five-year term.
She was elected unopposed, after the other two nominees for the position, Donal Magee of Killyclogher and Clogher’s Eugene McConnell, withdrew from the contest.
Accepting the position, the new chairman said she was acutely aware of the historical significance of the occasion.
“This is one momentous night in the history of Tyrone and also in the history of our Gaelic Athletic Association,” she said.
“Once again Tyrone has led the way in being the first county to elect a female to the position of county chairman.
“I am humbled and honoured that the clubs of Tyrone have seen fit to elect me here tonight.”
An election for the post of chairman has in recent years been rare in Tyrone, with a now established tradition of the vice-chair succeeding the outgoing chairman.
Mrs Jordan, a former secretary of her club, has been involved at county board level for the past decade, and has served on committees at national level.
Married with four grown-up children, she takes on the challenge of leading one of the largest, and latterly among the most successful, units of the 130-year-old association.
Club colleagues were among the first to congratulate the new Red Hand chairman.
Eglish St Patrick’s chairman Frank McKillion said: “It’s a proud occasion for Eglish GAC, and an historic day for the GAA in Tyrone.
“Roisin is an esteemed member of our club, a former secretary, and a very diligent official.
“Her administration skills have been of immense value to our club, and she has brought those skills to county board level. We wish her well in her new role.”
Not so long ago an almost exclusively male domain, GAA officialdom has made steady if unspectacular strides towards a measure of gender balance.
Donegal’s Noreen Doherty became the first woman to be elected as secretary of a county board in 1992.
Currently there are three female county secretaries – Anita Finnegan in Monaghan, Margaret Doyle in Wexford and Kildare’s Kathleen O’Neill. In Monaghan and Wexford, the assistant secretaries are also female.
The world of refereeing has also moved towards inclusion, and Cavan’s Maggie Farrelly made history earlier this year when she acted as sideline official at the Dublin-Kerry National Football League clash at Croke Park.