Junctions and service areasEdit
- Junction 1: Potters Bar,Changes from A1 road to Motorway standard, Access to South Mimms service area via interchange, A1(M) crosses under M25, .
- Junction 2: Hatfield (south).
- Junction 3: Hatfield, St Albans, A414.
- Junction 4: Hatfield (north), Hertford, A414.
- Junction 5: Welwyn Garden City.
- Junction 6: Welwyn Garden City (north), Welwyn.
- Junction 7: Stevenage, A602.
- Junction 8: Hitchin, Stevenage (north).
- Junction 9: Letchworth, A6141.
- Junction 10: Stotfold, becomes A1 Trunk road again.
At Hatfield the road passes through a 'Tunnel' That has the "Gallerias" Shopping Center on top of it.