Lay (river)

{{Short description|River in western France}}

{{One source|date=December 2021}}

{{Infobox river

| name = Lay

| native_name ={{native name|fr|Le Lay}}

| image = Mareuil-sur-Lay-Dissais 001.JPG

| image_caption = The Lay at Mareuil-sur-Lay-Dissais

| map = Lay (fleuve).png

| source1_location = Saint-Pierre-du-Chemin

| source1_coordinates= {{coord|46|42|34|N|00|42|37|W}}

| mouth_location = Bay of Biscay

| mouth_coordinates = {{coord|46|19|14|N|01|18|10|W|display=inline,title}}

| subdivision_type1 = Country

| subdivision_name1 = France

| length = {{convert|120|km|mi|abbr=on}}

| source1_elevation = {{convert|195|m|ft|abbr=on}}

| mouth_elevation = {{convert|0|m|ft|abbr=on}}

| discharge1_avg = {{convert|14|m3/s|cuft/s|abbr=on}}

| basin_size = {{convert|1750|km2|sqmi|abbr=on}}

}}

The Lay ({{IPA|fr|lɛ}}) is a {{convert|120|km|mi|adj=on}} river in the Vendée département, western France.{{Sandre|id=N3--0160|nom=Lay}} Its source is at Saint-Pierre-du-Chemin and it flows generally southwest. It flows into the Bay of Biscay between La Faute-sur-Mer and L'Aiguillon-sur-Mer, {{convert|20|km|mi|abbr=on}} northwest of La Rochelle.

Its main tributaries are the Yon and the Smagne.