Linfield Football Club is a Northern Irish professional football club, based in south Belfast, which plays in the NIFL Premiership â the highest level of the Northern Ireland Football League. The fourth-oldest club on the island of Ireland, Linfield was founded in 1886 by workers at the Ulster Spinning Company's Linfield Mill. Since 1905, the club's home ground has been Windsor Park, which is also the home of the Northern Ireland national team and is the largest football stadium in Northern Ireland. They train at Midgley Park which is beside the stadium. The club's badge displays Windsor Castle, in reference to the ground's namesake.