A proposed structure is an edifice in the early phase of its development, between the release of its design and approval by local authorities. The proposal must have a serious likelihood of being built, otherwise it is classified as a vision or a competition entry.

The prerequisite for this status - and for any structure's listing - is the completion and publication of its basic design specifications. (Until then there is not enough determined information to complete a listing.) In general a design rendering should exist, but if the project is important enough it can be listed as soon as basic specifications (exact location, floor count, and usage) are announced by involved parties.

A structure remains proposed as long as any likelihood of its future construction remains. It is not necessary for a construction schedule to be determined. If a proposal is no longer active, its status is changed to 'canceled'. Proposals which have not started construction remain listed as 'proposed' even is planning is suspended for any period of time; the term 'on hold' applies only to structures which have begun construction.