Setting Default Value in DropDown

hi, i have a country dropdownlist (asp.net server side control) where in i wish to set United States as first country from list of alphabetical countries in drop down. How should i do that?
Plus on selection of country the respective state gets fired up. So if USA is selected in country by default, the states need to be selected by default (Of USA of course!!!)
Below is the code of country dropdown.
Public Sub GetCountry(ByVal ddl As DropDownList)
            Dim dt As New DataTable
            Dim con As New SqlConnection
            Dim da As New SqlDataAdapter
            Try

                con.ConnectionString = ConfigurationManager.AppSett ...