The majority of the freeways and expressways in Ontario are 400-series highways; there are also some others which do not have that designation. The full list appears below.
The province also maintains freeways which are up to 400-series standards, yet are not numbered as part of the 400-series network. This is despite some of those freeways exceeding existing 400-series highways in size and traffic volume and despite some of them being connected to the 400-series network. Nonetheless, Ontario freeways do not receive a 400-series number unless they are designed to be complete controlled-access freeways for their whole length. The non 400-series routes listed below have significant open-access portions besides the freeway section, with the freeway segment typically being a small section not at the route's termini.
These include both municipal-constructed freeways and former provincial freeways downloaded to municipalities.