It is no longer the law in most common law jurisdictions today, yet 99-year leases continue to be common as a matter of business practice and conventional wisdom.
Under the traditional common law doctrine, the 99-year term was not seriously literal, but merely an arbitrary time span beyond the life expectancy of any possible lessee (user) or lessor (owner).
[3] The 40-year limit was based on the text The Mirror of Justices (book 2, chapter 27).
In the law of several US states, a 99-year lease will always be the longest possible contract for realty by statute, but many states have enacted shorter terms and some allow infinite terms.
[citation needed] Due to the influence of the ideas of Henry George at the time the Australian Capital Territory (ACT) was established in the early 20th century, all land in the ACT is held under 99-year leases, the first of which expired in 2023.