A truly remarkable record.  In my native Ireland, where Sandwich Tern 
is quite common, I never saw one inland in 20 plus years of birding. 

Quoting Matthew Medler <[log in to unmask]>:
> Hi All,
>
> For those who don't peruse the Northern New York listserve, I wanted 
> to get the
> word out that Bill Krueger found a SANDWICH TERN along the shore of Lake
> Champlain in Chazy, Clinton County, New York earlier today (31 August 2010). 
> This is a remarkable inland find, and I wanted to let Vermont birders 
> aware of
> its presence on the lake.  I've included Bill's two messages to 
> NNYBirds below. 
>
> Good birding,
> Matt Medler
> Ithaca
>
> Subject: NNYBirds:  Sandwich Tern
> From: "Bill Krueger " <billkrueger AT hotmail.com>
> Date: Tue, 31 Aug 2010 15:12:26 +0000
>
> A Sandwich Tern was present on the tire breakwater at Gilbert Creek Marina,
> Chazy, NY at about 10:00 this morning. It flew off unobserved when I tried to
> give Charlie Mitchell a look though the scope. We did not relocate it. 
>
> Bill Krueger
> Plattsburgh, NY
>
> Subject: NNYBirds:  Sandwich Tern Details
> From: Bill Krueger <billkrueger AT hotmail.com>
> Date: Tue, 31 Aug 2010 15:00:08 -0400
>
> As large or larger than the nearby Bonaparte's Gulls and noticeably 
> larger than
> Common Terns seen later, this bird had a yellow tipped
> black bill, a white forehead, and black cap with a crest. The black 
> of the cap
> extended well down its nape. It resembled but was smaller than
> Royal Tern. Its legs were black. All other particulars of size, shape and
> overall conformation were ternlike; it was not a gull. 
>
> Bill Krueger
> Plattsburgh, NY
>