| Club: | Louth county football team |
| Season: | 2021 |
| Manager: | Mickey Harte |
| League: | NFL D4 North |
| League Result: | 2nd (promoted) |
| Cup1: | All-Ireland SFC |
| Cup1 Result: | Did not compete |
| Cup2: | Leinster SFC |
| Cup2 Result: | Preliminary round |
| Prevseason: | 2020 |
| Nextseason: | 2022 |
The following is a summary of Louth county football team's 2021 season.
There was no O'Byrne Cup in 2021 due to the impact of the COVID-19 pandemic on Gaelic games.[1]
See main article: 2021 National Football League (Ireland).
| GK | 1 | Craig Lynch (Naomh Máirtin) | |
| RCB | 2 | Dan Corcoran (Geraldines) | |
| FB | 3 | Dermot Campbell (Dreadnots) | |
| LCB | 4 | Donal McKenny (St Mary's) | |
| RHB | 5 | Emmet Carolan (Newtown Blues) | |
| CHB | 6 | Niall Sharkey (Glyde Rangers) | |
| LHB | 7 | Eoghan Callaghan (Naomh Máirtin) | |
| MF | 8 | Bevan Duffy (St Fechin's) | |
| MF | 9 | Ciarán Byrne (St Mochta's) | |
| RHF | 10 | Liam Jackson (St Mary's) | |
| CHF | 11 | Sam Mulroy (Naomh Máirtin) (c) | |
| LHF | 12 | Ciarán Downey (Newtown Blues) | |
| RCF | 13 | Ciarán Keenan (St Mary's) | |
| FF | 14 | Conor Grimes (Glen Emmets) | |
| LCF | 15 | Ryan Burns (Hunterstown Rovers) | |
| Substitutes: | |||
| 16 | Leonard Grey (St Patrick's) for Corcoran | ||
| 17 | Declan Byrne (St Mochta's) for Burns | ||
| 18 | Dáire Nally (Newtown Blues) for Campbell | ||
| 19 | Conal McKeever (Clan Na Gael) for Duffy | ||
| 20 | John Clutterbuck (Naomh Máirtin) for Carolan | ||
Antrim and Louth shared the Division 4 title, as Louth had a championship game on 27 June 2021.
See main article: 2021 Leinster Senior Football Championship. The draw for the preliminary rounds and quarter-finals took place on 20 April 2021.[2]
See main article: 2021 All-Ireland Senior Football Championship. Due to the impact of the COVID-19 pandemic on Gaelic games, there was no back-door route into the All-Ireland Championship. Therefore, because Louth did not win the Leinster Championship, they did not qualify for the 2021 All-Ireland Championship.