Longford booked their semi-final berth following a comprehensive victory over Louth at Newtowncashel.
Longford's attacking duo of Larry Moran and Liam Connerton kept busy all evening and registered a healthy contribution of 1-10 between them.
The locals grabbed the perfect start and raced into a four-point lead. Their inside forwards Moran, Paddy Kiernan and Connerton all got off the mark in the opening ten minutes while Louth struggled to find any real headway.
The visitors had to wait over 16 minutes before they found their first point.
Ryan Burns kept them in touch with two long-range points that left a five-point deficit at the half-time interval.
After the break, Louth instigated a brief fightback when Conor Grimes struck a well-taken goal in the 39th minute. This, however, was premature and Longford wrapped up the contest in the final minutes when Liam Connerton closed out the contest with blistering goal that secures them a semi-final meeting against Dublin on March 18.
Scorers - Longford: L Connerton 1-4(1f), L Moran 0-6 (2f), S Kenny 0-2f, P Kiernan, L Sullivan, A Dalton, R Connor, D McGivney 0-1 each. Louth: R Burns 0-4 (3f), C Grimes 1-0.
Longford - C Farrell; R Sweeney, A Farrell, C Shields; L Sullivan, C Farrelly, D Reynolds; F Sheridan, A Dalton; R McNerney, S Kenny, R Connor; L Moran, P Kiernan, L Connerton. Subs: D McGivney for S Kenny (42), M Gorman for R Sweeney (47), A McBrien for L Sullivan (55), P Farrell for P Kiernan (57), V Hourican for R McNerney (57).
Louth - D Breen; A Smith, C Kirk, J Connolly; B Faulkner, D Marks, K Faulkner; J Stewart, W Campbell; R Quigley, E Lafferty, R Carr; R Burns, C Doyle, C Grimes. Subs: S Kilcoyne for A Smith (h-t), C Carthy for K Faulkner (h-t), J Hanna for D Marks (53), D McGuire for C Doyle (55).
Ref - D Hickey (Carlow)
Eirgrid Leinster U-21FC quarter-final (extra-time if necessary)
Offaly v Kildare, Portlaoise,
7.30, P Maguire (Longford)
Kildare, managed by Bryan Murphy who guided the county minors to Leinster success in 2013, enter this game with cautious optimism, but very mindful of last year's upset in Athy against the same opposition.
In 2014, the Lilywhites were reigning Leinster champions and would have been fancied for a good run, only to come a cropper at the first hurdle.
Offaly senior manager Pat Flanagan is also in charge of the U-21s, and rested the underage members of the senior panel for last Sunday's National League win over Wicklow.
Star forward Peter Cunningham is recovering from a shoulder injury. He is named in the subs, but is likely to make an appearance at some stage of what is sure to be a tightly-contested game.
Eoin Carroll and Conor McNamee sat out the senior team's match in Aughrim and will be fresh for action tonight.
Kildare will look to senior players Niall Kelly and David Hyland to power their performance. Kelly reached the Sigerson Cup semi-final with UCD and is in good form.
Forwards Chris Healy and Mark Sherry were on the Two Mile House side which won the All-Ireland Junior Club football title last year.
Odds: Offaly 2/5 Kildare 5/2 Draw 7/1