Eugene S. Stine's, Pennsylvania German Dictionary, published by the Pennsylvania German Society, 1996 defines Allemengel as "name applied in colonial times to the northwestern part of Lehigh Co. (PA) because of the the dire need of the early settlers." Dr. Stine's dictionary is based on the Lehigh-Northampton variant of the Pennsylvania German dialect. He grew up in Allentown in a bilingual home with English and PA Dutch both spoken. Looks like a better good definition to me.
Martin Keen