Few, if any, have as good a grasp on the province’s football heartbeat.
He grew up in Kilmovee in Co Mayo, a short jaunt to Roscommon out one road and an equally swift run up to Charlestown and into Sligo another way.
Yet, while the wellbeing of those three counties was always apparent to him, his greatest success as a manager came with Leitrim and Galway.
In a way, taking Leitrim to the Connacht title in 1994, their first since their only success in 1927, was every bit as big an accomplishment as guiding a star-studded Galway side to two All-Irelands.
He’s been back on the beat for close on two seasons now, helping Brendan Guckian try to work the oracle with Leitrim tomorrow evening they will try upset the odds and oust reigning Connacht champions Roscommon in Páirc Seán in Carrick-on-Shannon.
His familiarity with the health of Roscommon football is augmented by a few seasons helping the successful St Brigid’s club, but deep knowledge is not required to appreciate Leitrim are up against it tomorrow.
Leitrim have not beaten Roscommon since they last reached the Connacht final in 2000. The last seven games have gone Roscommon’s way, and the gap has been widening.
Five points separated the neighbours when they met in the 2010 Connacht semi-final, there was 12 between them a year later, 11 in 2014.
This is the third year they have met, in 2016 Roscommon won by 13 points, last summer it was done and dusted in the opening quarter and the Rossies were on their way to a 17-point win.
“They really put us away in the first 15 minutes of the game last year. We can’t allow that happen this time, we need to stay with them,” said O’Mahony.
He knows what it’s like to be with Leitrim when there is a big shock in the Connacht championship.
It wasn’t just the weather which had him and the Leitrim contingent sweating in the Bronx earlier this month when New York came within a whisker of dumping them out of the Connacht championship.
“I’ve been in New York a lot of times and that was the best performance I have seen from them,” said O’Mahony, after Leitrim had denied the Exiles their first championship win when they scored a last gasp point to win 0-19 to 1-15 after extra-time.
“If you were a neutral observer, or a New York supporter, you would feel hard done by to a certain extent. They did an awful lot of things right.
“Our lads, we knew it was going to be a battle when we came out. We had a very young and experienced side. Average age is about 23 if you take out Emlyn Mulligan and Paddy Maguire but the one thing about them is they never dropped the heads.
“They had a terrible start. 15 minutes, 1-4 to 0-1 down. Dug themselves back to lead by a point at half-time and in the first period of extra-time we had five chances and we missed them. They went down and got two points. Then they went three up.
“We could have thrown in the towel. And for young lads to keep the structure and win it on scoring points it will really stand to them.”
How much that trip and game will help them bridge the gap to their neighbours remains to be seen but O’Mahony has been around the block with enough teams to know that the whole experience could lift them.
“Survive something like that and spend five days together as a group like that, which you don’t usually do. And the bonding that takes place.
“But Leitrim, the place they are in, it will be totally underdogs and written off against Roscommon and rightly so. What this will help, it will help in the development long-term of this squad. There is nothing you can prepare for like the white heat of championship.
“That’s what you had there. Of all the New York teams that I saw over the years, this was the best equipped. Kevin McStay would kill to have Neil Collins, Kieran McGeeney would kill to have Jamie Clarke. Tom Cunniffe, I’m sure he would be in Stephen Rochford’s plans if he was at home.”
How much that trip to the United States will have helped Leitrim to develop will become apparent tomorrow evening in Carrick-on-Shannon.
Just how close these two counties are geographically is apparent from the fact that the county line comes right up to the town and there are many whose address is ‘Carrick-on-Shannon, Co Roscommon’.
But on the field, in recent years, they have been poles apart.