The English Newark for which (presumably) the sundry American Newarks are named is an unremarkable middle-sized market town in Lincolnshire in the East Midlands, on the Great North Road (and now bypassed by the A1) and the East Coast Main Line. It was the scene of a major siege and bloody capture during the English Civil War but nothing much since. The stress on the first syllable; the second vowel is a schwa. | 
