The border (presumably) on the far west end of the island. Left--looking east. Right--looking west. Inside the bushes there is a stone wall that appears to mark the border (property lines?). I asked a police officer and a couple of other locals, who confirmed the stone wall is the border. (see below)

 
Left--this sign is in the French side by about 150 meters or so. There is no sign entering the Dutch side on this road.
Left--looking toward the end of the stone wall (border) at the SW part of the island. Right--The end of the stone wall at the southwest corner if the island. Behind me is a cliff that falls into the ocean.
Another view of the end of the stone wall.
Left--the border as it continues to bisect the island.

Right--the stone wall immediate behind the boundary pillar on the main road between the two capitals.
Left--looking across the road. While the two sides share some elements of infrastructure, you can see where the power line ends at the border.

Right--a view of the border attraction, looking west.

 
The border monument on the main highway between Philipsburg and Marigot. There was an election going on while I was there (May 2003) on the Dutch side and the border is a very good place for campaign signs!! The wall above is directly behind this monument.
These shots are from the main highway that crosses the border approximately in the middle of the island--east of the lake. Left--looking toward French side. Right--looking toward the Dutch side. Notice that the pavement change is inside Dutch side by a fair distance.
This is probably the smallest international bridge in the world, smaller than the one in the Thousand Islands between the US and Canada. The photos are of the same bridge. Left--looking into Netherlands from France. Right--looking into France from Netherlands. At this point, the border is a shoreline border, so the bridge crosses over, and the dining area of the restaurant is in Sint Maarten, while the parking area is in St Martin.
This is the easternmost road crossing on St Martin at Oyster Bay. The border probably goes between the two big rocks. (Photo 2003)