Carl Martin
The White Wolves already have a clear lead at the top of the Supreme Division – and now have their first ever final to look forward to.
Louth booked their place at Park Avenue on Tuesday night, overcoming a 1-0 half-time deficit with a superb second-half performance.
Parramore started brightly and impressive striker Gavin Davies broke down the right and hit a perfect cross for Andy Dawson, who curled his shot over the bar.
The visitors threatened moments later when Gavin Wills hit a cross-cum-shot right across the face of the goal with nobody on hand to turn the ball into the net.
Parramore eventually took the lead after 11 minutes when Paul Billard hit a 25-yard free-kick around Town's defensive wall and into the bottom of Craig Wherry's net.
Louth struggled to get their usual slick passing game going against well-organised visitors.
It took them 15 minutes to threaten Mark Clements in the Parramore goal, James Archer hitting a long pass to Mark Wood. He played a delightful pass to Sam Smith, who saw his shot flash narrowly wide.
Parramore were unlucky on 17 minutes as Davies tried a spectacular overhead kick before Gallacher saw his long-range free-kick well saved by Wherry.
Smith was again unfortunate for Town, firing just wide after a good flick from Carl Martin, before Wood hit a 25-yard free-kick well over Clements' bar.
Both teams were forced to start the second half with 10 men as skippers Jordan Walden and Andy Rodgers were dismissed for an alleged altercation in the tunnel at the end of the first half.
Louth coped better with 10 and equalised nine minutes into the second half through Martin. The big defender rose beautifully to meet Smith's cross and send a powerful header into the top corner.
Within two minutes the game had turned around completely as Martin again headed home from Wood's corner to give Town a 2-1 lead.
Confidence spread and Town began knocking the ball around well and creating a threat with almost every attack.
Craig Dalton missed a great opportunity to extend Louth's lead when he headed into the side netting from Smith's corner.
Smith increased Town's lead with 70 minutes gone as he latched onto Woods through ball before producing a cool finish from the edge of the area.
Town had a strong penalty appeal turned down moments later as Kurt Crossley burst into the area and appeared to be brought down by Lee Gilliott, but the referee was not interested.
Crossley gained his revenge two minutes later as he was ran onto Wherry's long clearance before curling a fantastic shot into the top corner to give Town a 4-1 lead.
Louth poured forward and scored again with eight minutes remaining as Smith grabbed his second, powering into the penalty area before producing another cool finish.
Parramore never gave up and managed a consolation with four minutes remaining when Davies capped a fine individual performance by poking home a cross from substitute Sean Grice.
Town return to league action on Saturday when they face a trip to Kimberley Town (3pm).