David Ross Locke (his pseudonym was Petroleum V. Nasby) (1833 - 1888) was a U.S. journalist. He edited, and wrote for, the Toledo, Ohio newspaper, the Toledo Blade.

Locke's most famous work, the "Nasby Letters," was written in the character of, and over the signature of, "Petroleum V(esuvius) Nasby," a Copperhead and Democrat. They have been described as "The Civil War written in sulphuric acid."

"Nasby" loudly championed the cause of the Confederate States of America from secession onward, but did little to actively abet it. After being conscripted into the Union Army he deserted to the Confederates, joining the fictional "Pelican Brigade." However, he found life in the Confederate Army "tite nippin" and soon deserted again. By the end of the Civil War he was back in civilian life.

The "Nasby Letters," written in the semi-literate spelling used by other humorists of the time, were intended to rally support for the Union cause, since "Nasby" himself was portrayed as a thoroughly detestable character---a supreme opportunist, bigoted, work-shy, often half-drunk, and willing to say or do anything to get a Postmaster's job. At the time the Letters were written, Postmasterships were political plums, offering a guaranteed federal salary for little or no real work. Until the glorious day when he received a "Post Orfis" from Andrew Johnson "Nasby" worked, when he worked, most frequently as a preacher. His favorite Biblical texts, unsurprisingly, were the ones that were used by Southern ministers to "prove" that slavery was ordained by the Bible.

Abraham Lincoln loved the "Nasby Letters," and quoted them frequently. He is said to have said: "For the genius to write such things, I would gladly give up my office."

After the Civil War, "Nasby" went on to comment on Reconstruction. He settled in several different places, most notably "Confedrit X Roads, wich is in the Stait of Kentucky," a fictional town full of idle, whisky-loving, scrounging ex-Confederates, and a few hard-working, decent folk, who by an amazing coincidence were all strong Republicans. He travelled frequently, sometimes not entirely voluntarily ("Nasby's" habit of borrowing money he never repaid, and running up tabs at the local saloon often made him unpopular) and continued to comment on the issues of the day.

Locke discontinued the "Nasby Letters" a few years before his death, since the times had changed and "Nasby" was no longer topical. While the semi-literate spelling in which they are written has often discouraged modern readers, it can also be seen as a point of characterizing "Nasby."

Several collections of the "Letters" came out in book form, some illustrated by Thomas Nast, who was a friend and political ally of Locke.