If you are walking in the Dales then there are three obvious choices for the range of maps to use.
The Ordnance Survey Landranger, 1:50K scale maps, cover the vast majority of the Yorkshire Dales with a single sheet. That's sheet 98 Wensleydale & Upper Wharfedale the coverage area of which we show on the map on on the right.
Ordnance Survey Landranger, 1:25K scale maps, now cover the main part of the Yorkshire Dales in two double sided sheets OL2 and OL30 as part of their Outdoor Leisure series but you may also need OL19 if you are heading for the northern end of the park:
|OL2 -||Yorkshire Dales|
(coverage shown in red on our map)
|OL19 -||Howgill Fells|
(coverage shown in green on our map)
|OL30 -||Yorkshire Dales - N & C|
(coverage shown in blue on our map)