I have a pre existing layer of 1km x 1km grid squares, which is aligned with the 10km squares of the British National Grid:

enter image description here

I want to create another 10km x 10km square grid on top to highlight the 10km grid lines. I have been trying to create a grid using the create fishnet tool, but I can't figure out how to align the resulting grid with my previous one. Does anyone know if there is a way to align a fishnet with a preexisting feature, or if there is any other way to achieve this aim? Basically I want the black gridlines on the green transparent grid layer below to line up with the blue gridlines on the basemap layer underneath. The projection of all the layers is British National Grid.

enter image description here

  • The Fishnet tool includes a reference source. You can either create the 10km from the 1km or vice versa. You can also manually specify the origin.
    – Vince
    Commented Nov 27, 2019 at 15:21
  • Could you please tell me how I input a reference? I can't see any option to use another feature as a reference source on the menu for the Create Fishnet in ArcMap 10.5. There is an option to use another layer to define the extent, but that's it.
    – Yusef_S
    Commented Nov 27, 2019 at 15:46
  • Yup, that's the one.
    – Vince
    Commented Nov 27, 2019 at 15:50
  • If it's aligned with the 10km squares of the British National Grid why not using the already existing grid ? seem simpler than recreating it....
    – J.R
    Commented Nov 27, 2019 at 16:26
  • A quick fix would be to select all features, toggle edit and drag to snap it to original grid
    – B-C B.
    Commented Nov 27, 2019 at 17:59

1 Answer 1


For BNG fishnet you can set the origin:

  • left:0
  • bottom: 0
  • Top: 1 300 000
  • Right: 700 000

enter image description here

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