The OL postcode area, also known as the Oldham postcode area, is a group of sixteen postcode districts in north-west England, within seven post towns. These cover northeast Greater Manchester (Oldham, Rochdale, Ashton-under-Lyne, Heywood and Littleborough), and small parts of east Lancashire (Bacup) and West Yorkshire (Todmorden).
Mail for the OL postcode area is processed at Manchester Mail Centre, along with mail for the M, BL and SK postcode areas.
The approximate coverage of the postcode districts are:
|- ! OL1 | OLDHAM | Chadderton, Higginshaw, Oldham | Oldham |- ! OL2 | OLDHAM | Heyside, Royton, Shaw | Oldham |- ! OL3 | OLDHAM | Delph, Denshaw, Diggle, Dobcross, Greenfield, Uppermill | Oldham |- ! OL4 | OLDHAM | Austerlands, Grasscroft, Grotton, Lees, Lydgate, Oldham, Scouthead, Springhead, Waterhead | Oldham |- ! OL5 | ASHTON-UNDER-LYNE | Mossley, Mossley Cross | Tameside |- ! OL6 | ASHTON-UNDER-LYNE | Ashton-under-Lyne (centre and east) | Tameside |- ! OL7 | ASHTON-UNDER-LYNE | Ashton-under-Lyne (west), Guide Bridge | Tameside |- ! OL8 | OLDHAM | Bardsley, Oldham | Oldham |- ! OL9 | OLDHAM | Chadderton, Oldham, Westwood, Freehold | Oldham |- ! OL10 | HEYWOOD | Heywood | Rochdale |- ! OL11 | ROCHDALE | Rochdale (south), Ashworth, Balderstone, Castleton, Norden | Rochdale |- ! OL12 | ROCHDALE | Rochdale (north), Buckley, Facit, Great Howarth, Healy, Hurstead, Shawforth, Wardle, Whitworth | Rochdale, Rossendale |- ! OL13 | BACUP | Bacup, Britannia, Stacksteads | Rossendale |- ! OL14 | TODMORDEN | Cornholme, Todmorden, Eastwood, Walsden | Calderdale |- ! OL15 | LITTLEBOROUGH | Littleborough, Shore, Smithybridge, Summit | Rochdale |- ! style="background:#FFFFFF;"|OL16 | style="background:#FFFFFF;"|LITTLEBOROUGH | style="background:#FFFFFF;"| | style="background:#FFFFFF;"|non-geographic |- ! OL16 | ROCHDALE | Rochdale (east), Burnedge, Firgrove, Hurstead, Milnrow, Smallbridge, Thornham | Rochdale |- ! style="background:#FFFFFF;"|OL95 | style="background:#FFFFFF;"|OLDHAM | style="background:#FFFFFF;"|British Gas | style="background:#FFFFFF;"|non-geographic