Standard&Poor's Ratings Services assigned its 'AAA' long-term rating and stable outlook to Williamson County, Texas' series 2010 limited-tax refunding bonds. Standard&Poor's also affirmed its 'AAA' long-term rating and 'AAA' underlying rating (SPUR) on the county's outstanding parity debt. The ratings reflect what we regard as the county's: Deep and diverse tax base, with access to the Austin metropolitan statistical area; Successful management of growth-related pressures; and Consistently strong financial management and strong performance. Mitigating factors, in our opinion, include the county's: High overall net debt levels; and Additional infrastructure needs (mainly roads) to meet growth pressures. Officials will use bond proceeds to refund outstanding debt for savings. Williamson County is located in central Texas and encompasses