The old name is associated with the famous Tanglewood Music Center in Massachusetts, said an Intel spokesman. Many of the engineers working on the project came to Intel from Massachusetts-based Digital Equipment and live and work in the state.Source: C|net
Tukwila is a town in Washington about 15 minutes away from Seattle. The mayor's name is Steven Mullet.
Intel typically selects geographic place names for code names to avoid copyright and trademark disputes. Many of the code names derive from towns in the Pacific Northwest, but other names are creeping in. The Pentium M chips carry Israeli code names such as Dothan and Banias because the chips are designed in Israel.
Intel renamed Tanglewood processor to Tukwila.

Intel has changed the name of his next Itanium processor from Tanglewood to Tukwila, in order to avoid a trademark dispute with the Tanglewood Music Center.