sql get all existing values??

Which part of the query takes too long?
select distinct [year] from [dbo].[YTDDate] as a with(nolock)
or
select distinct Region, County from [dbo].[Geographics] as b with(nolock)
?
How many rows is it returning? How many rows are in the original tables?

You can remove the distinct from the outer query, like so:

select
a.[Year],
b.Region,
b.County
from
(select distinct [year] from [dbo].[YTDDate] as a with(nolock)) a,
(select distinct Region, County from [dbo].[Geographics] as b with(nolock) ) b

If that doesn't improve the speed enough, add this index on the Geographics table:

create nonclustered index [Geographics__ix_region_county] on dbo.Geographics ( Region, County ) with ( fillfactor = 95, sort_in_tempdb = on );

Then try the original code again.