Portland, Oregon, is well known for its relatively unique urban growth boundary (UGB), a very tight form of zoning designed to control sprawl. The UGB has recently been criticized for raising housing prices. From a theoretical perspective, the UGB will put upward pressure on land and thus housing prices, but the magnitude of this effect is uncertain. Increasing density should substitute for higher land prices, partially offsetting any reduction in the supply of housing. In addition, at any given moment, speculative factors influence housing price levels in bull markets such as the one Portland has been experiencing. This article presents an econometric analysis assessing these conflicting effects. We find the UGB has created upward pressure on housing prices, but the effect is relatively small in magnitude.