The letters in this collection were all signed by Walker as Treasury Secretary, between 1846 and 1848, and were addressed to Mr. C.W. Lawrence, who was the Collector of Customs at the Port of New York during this period. They deal primarily with interpretation of tariff acts and enforcement of customs regulations as applied to specific cases at the port. Included are details about payments of import duties and drawbacks, and information regarding expenses for maintaining of a warehouse on the "Atlantic dock" that was used by the customs district, and an account of an appraiser being fired for "irregularities in performance of his duties." Walker also authorized several payments for work done on a new revenue brig that was under construction in 1848. Numerous references are found to the tariff acts of 1842 and 1846. There are description of articles being imported into New York, and the names of many revenue schooners and steamers are also mentioned.