At the time of its issue, the basic domestic postage rate was 3 cents per 1/2 ounce for mail sent under 3000 miles and 10 cents per 1/2 ounce for mail over 3000 miles. As such, the 12 cent stamp saw limited usage domestically, being an option for mail under 3000 miles but weighing more than 1 1/2 ounces (about the equivalent of 9 sheets of copier paper). Transcontinental domestic usages are virtually unknown, as 10 cent stamps were usually available and there was no small multiple of the 10 cent rate that intersected with a multiple of the 12 cent stamp. Commercial and legal correspondence did periodically reach the threshold as can be seen in the following examples:
In addition to the basic postage rate for what would now be considered first class mail, other rates and services were available. Carrier services to the post office and local or drop postage rates of 1 or 2 cents (after Jan 1, 1863) could be used if the item was not being sent between post offices. Changes in regulations allowed stamps to be used for registration services and forwarding fees are additional domestic usage's where the 12 cent stamp can be found, though these are less common (see illustrations):
Figure 8. Changes in regulations in June 1867 mandated that stamps pay registration fees. Above, a 12 cent stamp with and "F" grill pays part of the 15 cent registration and 3 cent postage fees for this March 1869 envelope from Olmstead, OH to Ovid, MI which was then forwarded at no additional charge to the recipient at Elsie, MI. The 15 cent registration fee was in effect from January 1, 1869 to January 1, 1874.
As the 12 cent stamp saw somewhat limited use and remained in stock for years, especially in smaller post offices, it can also be found used in conjunction with later issues, including the 1869 pictorials and the 1870s Banknote issues.