This narrow Newport Street is on the left edge halfway down this map segment http://www.motco.com/Map/81002/SeriesSearchPlat...
The overlays that highlight 17th century London features are approximate and derived from:
Open location in Google Maps: 51.511860, -0.127834
Mary • Link
Newport Market is certainly a set of very narrow streets at the extreme left edge of this map as it first appears when summoned. However, scroll south and west a little, and you will find that Newport Street itself is a broader street that runs westward of Long Acre.
Chart showing the number of references in each month of the diary’s entries.