Thomas Sprague to William H. Seward, May 3, 1861

Hon. WILLIAM H. SEWARD, Secretary of State:

SIR: I have within a few days received information that I know to be entirely reliable, that it is the intention of the secessionists to take possession of the peninsula of Lower California, Mexico, as one of the preparatory steps to the acquiring of a portion or the whole of Mexico. Having possession of the peninsula of Lower California, their intention is to cut off our commerce with Mexico, seize the Panama steamers, and with the aid of the treasure so acquired to be able to extend their conquest to Sonora and Chihuahua at least. The possession of the peninsula of Lower California is absolutely and indispensably necessary to the proper advancement and protection of the Pacific interest . of the United States. The native-born population of this State, without one solitary exception, will join the secessionists. The most of the Mexicans and French will do the same. Rather than the filibustering secessionists should get possession of the peninsula of Lower California I think our Government quite warranted (in case no arrangement can be made with the Mexican Government for its purchase) in taking possession of it for our own protection; at least to hold it as against the designs of the secessionists. For information in relation to the peninsula of Lower California, I refer you to my last report to Secretary Cass.

With high respect, I remain,

your obedient servant,