This scarce map depicts the region at a very large scale, depicting county and town boundaries, as well as those of public and ungranted lands. Coverage extends from Portsmouth and Manchester in the south as far north as Mount Washington, and much detail is given for the White Mountains. Many individual peaks are named—though oddly not those of the Presidential Range. Some well-known landmarks are also identified, including the Crawford and Notch Houses, the Flume, and the Lafayette Hotel.
The most prominent features, however, are the many rail lines transecting the region. Mapmaker Conant is identified as the Engineer for the Cocheco Railroad, and presumably this map was produced to promote the interests of his employer. The Cocheco was chartered in 1847 to run from Dover, New Hampshire to Meredith along the northwest shore of Lake Winnipesaukee, which would have rendered the line by far the most direct route from the coast to the Lakes Region. In reality the Cocheco never actually made it beyond Alton Bay at the southern foot of the lake, which presumably explains its depiction on the map as a solid line from Dover to Alton Bay and a dotted line from thence to Meredith.
This is by far the largest-scale depiction of the region since that on Philip Carrigain’s New Hampshire by Recent Survey (1816). A close comparison of areas of segments of the two maps strongly suggests that Conant employed Carrigain’s work as a base map, updating the topography in places and adding much new data for roads, railroads and other features of the human landscape.
This map is sufficiently uncommon that it has gone unnoticed by some well-informed writers on White Mountains maps: For example, Apt’s article on George Bond treats Bond’s 1853 map as the first map of the region. One writer who did catch it is David Cobb, whose Maps of New Hampshire locates five institutional examples.
I have found no record for a “Swett’s Zincography,” though Stauffer mentions a C.A. Swett responsible for engraving several maps of Boston between 1860-65 (I:263). Zincography was developed in the mid-19th century and involved elements of both etching and lithography: A sheet of paper bearing an original image in ink was laid on to a thin zinc plate. Acid was then applied to the paper, passing through the un-inked areas to etch the plate below, with the result that the image to be printed stood out from the plate in very slight relief. The plate was then prepared with a resist, with the result that only those areas in relief would accept ink, and the image was then printed on a lithographic press.
Bent, Bibliography of the White Mountains, p. 84; Cobb, Maps of New Hampshire, #201. Not in Apt, Maps of the White Mountains of New Hampshire or Phillips, List of Maps of America.
 Adam Apt, “Harvard Astronomer George Phillips Bond and His Role in Mapping the White Mountains,” in Historical New Hampshire, vol. 57 nos. 1-2 (2002), pp. 39-56.