Above map modified from "© OpenStreetMap contributors". The red dots represent baptisms of BROOKER (including derivations such as Broker, Brocker, etc) between 1550 and 1600. The larger the red dots, the more baptisms in that parish.
The area focuses on South-East England. There was also a secondary cluster in Warwickshire, and stray families in Manchester, Yorkshire, Devon, and Norfolk. However, I have not catered for all of those on the above map. See the below larger scale map for Brooker baptism counts in those areas by county.
The Blue dots and notes mark ancestral birthplaces and dates of my recorded surname ancestors in Berkshire, Oxfordshire, and Deptford, London. My line traces back reasonably securely to a John Brooker born at Long Wittenham, Berkshire, circa 1722.
The Purple dot and text represents Thomas Chandler of Basingstoke, Hampshire. Living there circa 1740's, he appears to have shared my Y-DNA markers L-SK1414 judging by some of his Chandler surname descendants that have tested. At some point before 1722, we must have shared Y line (paternal) ancestors.
From this map I can conclude that during the late 16th Century, the BROOKER surname was most common in Sussex, Kent, Surrey, and Hampshire. There was a secondary cluster in Warwickshire.
Distribution of BROOKER baptisms AD 1550 - AD 1600 by English County. County boundaries modern, but East and East Surrey united for historical purposes. Includes records of derivations of Brooker surname.
Surname Origin
This interesting surname derives from two possible origins. Firstly it may be of English topographical origin from the Old English word "broc", a brook, stream, plus the agent suffix "-er", used to describe a dweller at, hence "dweller at the brook". There is also a place called Brook in Kent and Wiltshire, from the same Old English word "broc" as above. Also the name may be an occupational name used to denote a broker, originating from the Anglo-French word "brocour", one who sells an agent in business transactions. The earliest recordings of the surname appear in the 13th Century (see below). John le Brouker was recorded in the 1327, Subsidy Rolls of Sussex. William le Brocker was listed in the 1326, Feet of fines Rolls. The Close Rolls in 1332, record a Elena Brocker. Kirby's Quest for Somerset recorded an Adam Brocker in 1328. Geoffrey Broker, aged 17, an immigrant to the New World, sailed aboard the "Merchant's Hope", bound for Virginia in July 1635. The first recorded spelling of the family name is shown to be that of William Brokere, which was dated 1296, Subsidy Rolls of Sussex, during the reign of King Edward 1, "The Hammer of the Scots", 1272 - 1307. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.
Discussion
Some more recent Brooker surname distributions.
Brooker Surname Study