Gruaro is a medieval origin town in the eastern Veneto countryside near the border with Friuli.

On a tablecloth, from the Church of San Giusto, blood stains were produced by a consecrated affirma remained among the folds of the fabric.

Today the relic is custodied in Valvasone's church (a bigger town north of Gruaro) for the will of the feudal lords of that time.

The town of Portogruaro, which rises on the banks of the Lemene river, was originally the port of Gruaro for trades, which later became independent.

Gruaro is west of road SS463, east of the motorway A28 and south of the Friuli's border.