The Condensate Wilderness was a region of space to which the Tenth Doctor, Martha and Jack were introduced in the year 100,000,000,000,000. It was located between the planets Malcassairo and Utopia.
Based on Professor Yana's description, the Wilderness was considerably closer to Malcassairo than Utopia. Beyond Utopia lay "the Wildlands" and the Dark Matter Reefs. (TV: Utopia)