防火道是植被或其他易燃物品的一个间断，用来制止或减慢山火的蔓延。防火道可以是一条马路：从一条小径到一条高速公路都有，甚至是一条沿着山脊被除去植被而不作任何其他功用的路。森林覆盖的土地一般都有许多天然的防火道网络。防火道若要发挥其功用，必须配合适当的消防灭火努力才行。即便如此，有些山火还是会不受控制的。在南加州火灾季节最严重的时候，狂风将一块块像地毯那么大正燃烧着的余烬吹过八条行车道的高速公路；1988年黄石国家公园的森林大火中，余火未尽的木炭居然可以越过一条一英里宽、六百呎深的天然峡谷——路易斯峡谷(Lewis Canyon)。世界上最昂贵的防火道是1906年旧金山地震之后，为制止已失控的大火继续蔓延，人们将整条Van Ness大道连房子都用炸药炸掉了。

A firebreak (also called a fireroad, fire line or fuel break) is a gap in vegetation or other combustible material that acts as a barrier to slow or stop the progress of a bushfire or wildfire. A firebreak may occur naturally where there is a lack of vegetation or "fuel", such as a river, lake or canyon. Firebreaks may also be man-made, and many of these also serve as roads, such as a logging road, four-wheel drive trail, secondary road, or a highway.