Lac d'Ilay

Infobox lake
lake_name = Lac d'Ilay
Lac de la Motte
image_lake =
caption_lake =
image_bathymetry =
caption_bathymetry=
location = Jura department, Franche-Comté
coords = coord|46|37|34|N|5|53|51|E|region:FR_type:waterbody_source:dewiki|display=inline,title|name=Lac d'Ilay (Lac de la Motte)
type =
inflow =
outflow =
catchment =
basin_countries = France
length = 1.9 km
width =
area = 0.72 km²
area_scale = 5
depth =
max-depth = 32 m
volume =
residence_time =
shore =
elevation = 774 m
islands = 1 (Île de la Motte)
cities =
frozen =

Lac d'Ilay (or Lac de la Motte) is a lake in the Jura department of France. It has a surface area of 0.72 km².

It is located in the municipalities of Franois and La Chaux-du-Dombief.