Louth have reached their first Leinster football final in 50 years after a 1-15 to 2-10 win over Westmeath at Croke Park.
Midfielders Paddy Keenan and Brian White claimed two points each as Louth led by 0-08 to 0-05 at the break.
Westmeath bounced back on the restart with Paul Bannon netting a 48th minute penalty, but this was cancelled out by a Colm Judge goal.
Martin Flanagan added a 65th minute goal for Westmeath, but Louth held on for a famous Croke Park victory.
Louth, conquerors of Longford and Kildare in previous rounds, began this game in determined fashion as they raced 0-04 to 0-00 clear by the seventh minute.
Scores from Brian White (0-02), Paddy Keenan and Shane Lennon set the Wee County side off to the perfect start, with Louth building well from defence to attack.
The returning Dessie Dolan got Westmeath off the mark with his only point of the game, and after Denis Glennon's 11th minute free bounced back off the post, it broke for corner forward Paul Greville to half Louth's lead.
Keenan helped Louth boss the midfield sector and showed great attacking prowess, in addition, when he took a pass from Adrian Reid and claimed his side's fifth point.
Teenager Ger Egan, who was making his first Championship start, landed a superb point for Westmeath in the 17th minute from an acute angle, before Reid quickly restored Louth's three-point advantage.
Westmeath knocked over some fine points in the opening half, including a 21st minute effort from Paul Bannon, but a match-ending injury to Derek Heavin soon after, which held up the game for five minutes, was a setback.
Pat Flanagan's side got back on track as Glennon reduced the arrears in the 29th minute, but disappointing Dolan and Glennon both sent scoring chances into the welcoming arms of Louth goalkeeper Neil Gallagher.
At the opposite end, Lennon and Colm Judge tagged on scores as Louth broke into a 0-08 to 0-05 lead for half-time.
Westmeath, who beat Wicklow for their first competitive win of the year recently, made a lightning quick start to the second half. Greville grabbed his second point inside 20 seconds of the restart.
Indeed, the Lake County outfit looked hungrier in the third quarter, outscoring their opponents by 1-02 to 0-03 during a very good spell.
Westmeath's goal was a penalty knocked home by Paul Bannon. The strike cut the deficit to the minimum in the 48th minute after substitute Padraic Smith and White had fired over for Louth.
The men in red, willed on by manager Peter Fitzpatrick, showed great determination as they scored 1-03 without reply, including a 58th minute goal from Colm Judge goal.
It was a free-flowing move from Louth which led to the goal as Westmeath's Glennon was dispossessed in an attacking situation and substitute Derek Maguire thundered through before unselfishly passing for Judge to supply the killer finish.
Despite Mark Brennan cancelling out Greville's fifth point, Westmeath had more in the tank and mounted a late challenge.
They were handed a lifeline in the 65th minute when substitute Flanagan dummied and then knocked a well-placed shot straight into the net from a tight angle. Glennon raised a white flag in the next play to make it a one-point game and add to Louth's nerves.
But Judge popped up to land the match-winning score for the Wee men, sweeping onto his right to find the target from 30 metres out. Louth's defence stood tall in the dying minutes to see out the win, although John Smyth and Bannon will both have nightmares about failing to convert late chances.
Scorers: Louth: C Judge 1-02 (0-01f), B White 0-04 (0-03f), P Keenan 0-03, S Lennon 0-02, M Brennan, A Reid, P Smith, D Maguire 0-01 each
Westmeath: P Greville 0-05 (0-02f), P Bannon 1-01 (1-00 pen), M Flanagan 1-00, D Glennon 0-02, D Dolan, G Egan 0-01 each
LOUTH: N Gallagher; E McAuley, D Finnegan, R Greene; R Finnegan, M Fanning, J O'Brien; P Keenan, B White; A McDonnell, M Brennan, A Reid; C Judge, S Lennon, JP Rooney.
Subs used: P Smith for McDonnell (half-time), D Maguire for Rooney (53 mins).
WESTMEATH: G Connaughton; F Boyle, D O'Donoghue, K Maguire; M Ennis, K Martin, D Harte; D Duffy, P Bannon; D Heavin, C Lynam, P Greville, D Dolan, D Glennon.
Subs used: J Smyth for Heavin (22 mins), J Keane for O'Donoghue (46), M Flanagan for Lynam (54), T McDaniel for Egan (61), D Healy for Martin (64).
Referee: Syl Doyle (Wexford)
