LANDED CLOSED PORTION OF RWY.

Narrative

I FLEW FROM WALLA WALLA; WA; TO ROCK SPRINGS; WY. I CALLED AND RECEIVED A STANDARD BRIEFING FOR A VFR XCOUNTRY PRIOR TO DEP FROM WALLA WALLA FSS. UPON ARR AT ROCK SPRINGS; I CALLED CASPER FSS TO CLOSE MY FLT PLAN. I THEN CALLED UNICOM FOR AN ARPT ADVISORY. I WAS ADVISED THE WINDS WERE FAVORING RWY 27. I ENTERED A L DOWNWIND FOR RWY 27 AND PROCEEDED IN L TFC TO THE RWY. AFTER LNDG THE OTHER PLT WITH ME NOTICED COLORED PAPER OR PLASTIC SECURED TO THE RWY SURFACE; WE LATER FOUND OUT THAT THE FIRST 5000 FT (APPROX) OF RWY 27 WAS CLOSED FOR CONSTRUCTION. ON LEAVING THE ARPT WHILE ON A TYPICAL L DOWNWIND POS FOR A TWIN I LOOKED FOR THE RWY MARKINGS THAT HAD BEEN NAILED TO THE RWY AND WAS UNABLE TO SEE THEM. AS TO WHY I BELIEVE I LANDED ON THE CLOSED SECTION OF THE RWY. WALLA WALLA FSS FAILED TO ADVISE ME OF THE NOTAM. ROCK SPRINGS UNICOM FAILED TO ADVISE ME OF THE NOTAM. THE RWY MARKINGS WERE NOT DISCERNABLE FROM DOWNWIND DUE TO STRONG XWINDS AT A UNFAMILIAR ARPT. I WAS INATTENTIVE ON SHORT FINAL WHEN I COULD HAVE SEEN THE MARKINGS.