Click once to enlarge, and once again.  More images of individual towns.

Operation Sea Lion, also written as Operation Sealion (German: Unternehmen Seelöwe), was Nazi Germany’s code name for the plan for an invasion of the United Kingdom during the Battle of Britain in the Second World War. Wikipedia

Militärgeographische Einzelangaben über England
Maps of England showing features of military significance

Militärgeographische Objektkarten mit Objektbildern
Maps of military installations with photographs.

Background information
In preparing for the invasion of Great Britain (Operation Sea Lion), a vast amount of information, including maps and photographs, was assembled by the German military. The maps in this collection were arranged in groups, based on the Ordnance Survey Quarter-inch Fourth Edition sheet lines, and distributed in pale green A4 size folders, which also included a book of postcard-sized photographs.

Thus, each numbered folder has a quarter-inch map of the area, a book of photographs and large scale plans of significant towns. The quarter-inch (1:250,000) maps use an extensive list of purple symbols for industrial sites (e.g. chemicals, waterworks, textiles, electricity) and red symbols for strategic sites (e.g. hospitals, airfields, radio stations, barracks). The large scale plans are usually 1:10,000 scale (metric six-inch), and again are an Ordnance Survey base map with coloured symbols showing sites of military significance such as airports, railway workshops, docks, bridges. Such sites are often illustrated in the book of photographs, the captions of which give a map location for each site, and each mapped site gives the book illustration number.

Sheet size is usually 18.5″ by 12.5 inches, with larger combined sheets showing some towns on a single sheet.

The town maps are very attractive, being printed in brown (rather than black), with blue water.
The various coloured symbols stand out clearly, are easily seen and are quite striking. The delicate black bridge symbols are especially noticeable and numerous, as are the red boundaries of railway stations and goods yards. Basically, for each town these maps show all locations that the Germans thought to be strategically important. They also double as a large scale pre-war Ordnance Survey map.

All folders were issued in 1941 or 1942 and are headed : Nur für den Dienstgebrauch! : For Official use only.

Generalstab des Heeres. Abteilung für Kriegskarten und Vermessungswesen (IV. Mil.-Geo.). Berlin 1941 (or 1942).
Military High Command / Department of Military Cartography and Surveying (IV.Mil.-Geo.) / Berlin 1941 (or 1942).

Two sets of all eleven folders are available, as listed below.
Individual town maps are also available.

Sets 2 and 3
Condition
Overall, the maps are in very nice condition, and are usually internally bright, with any damage being slight, usually confined to dusty edges, slight foxing, small marks, and very occasionally a light water stain or small tear to map edge.

The pale green used for folder and book covers has faded in places, where it is now a light brown colour.

The book from folder 4 is lacking from both sets. All other items are present.

Set 2
Folder 8 is torn along the spine, otherwise folders and maps are in good clean condition as described above. The contents, detailed town maps, area maps and photographs are listed in full below.

Set 2, eleven folders of town maps, area map and books of photographs £6,000.

Set 3
The largest folders, 4, 6 and 8 are badly torn in places. Other folders have small tears. Otherwise folders and maps are in good clean condition as described above. The contents, detailed town maps, area maps and photographs are listed in full below.

Set 3, eleven folders of town maps, area map and books of photographs £5,800.

Full details for both sets are as follows :

Notes
1. English will be used in this listing.
2. Notation examples : Newcastle is on three sheets : BB 3a, b, c, with Sunderland on a combined sheet BB 3.
Keighley is on two sheets : BB 9ae, af.

Folder 1. The Border
1. 1:250,000, Sheet 1, The Border (31 December 1941)
2. Town plans 1:10,000 (Dated 15.v.1942)
Carlisle : BB 2a
Newcastle : BB 3a, b, c
South Shields : BB 3 Combined sheet
Sunderland : BB 3 Combined sheet
3. Book of photographs (15 May 1942, 45 pages)
Folder 2. [North Central] Nördliches Zentralgebiet
1. 1:250,000 : Sheet 2, North Central (February 1942)
2. Town plans 1:10,000 (Dated 30.iv.1942)
Barrow in Furness : BB 8a, b
Preston : BB 8c, d
Accrington : BB 9e, f
Blackburn : BB 9g, h
Keighley : BB 9ae, af
3. Book of photographs (6 May 1942, 45 pages)
Folder 3. [England, North East] Nordost-England
1. 1:250,000 : Sheet 3, England, North East (1 December 1941)
2. Town plans 1:10,000 (Dated 30.iv.1942)
Middlesbrough : BB 6b, c, d, e
York : BB 10 Combined sheet
Kingston upon Hull : BB 10 Combined sheet
3. Book of photographs (30 April 1942, 38 pages)
Folder 4. [North Wales and Manchester] Nord-Wales und Manchester
1. 1:250,000 : Sheet 4, North Wales and Manchester (15 March 1942)
2. Town plans 1:10,000 (Dated 15.iii.1942)
Oldham : BB 12a, b, c, d
Manchester : BB 12e, f, g, h, i, k, l, m, n, o, p, q, r, s
Bolton : BB 12t, u
Warrington : BB 12v, w, x, y
Liverpool : BB 12aa, ab, ac, ad, ae, af, ag, ah, ai
Wolverhampton : BB 16 Combined sheet
Stoke on Trent : BB 16e, f
3. Book of photographs (31 March 1942, 70 pages) Lacking from Sets 2 and 3.

Folder 5. There was no Sheet 5 in this Ordnance Survey quarter-inch series, hence no German folder.

Folder 6. [North Midlands] Nord-Midlands
1. 1:250,000 : Sheet 6, North Midlands (31 December 1941)
2. Town plans 1:10,000 (Dated 15.i.1942)
Burnley : BB 9a, b, c, d
Halifax : BB 9i, k, l, m
Bradford : BB 9n, o, p
Leeds : BB 9q, r, s, t, u, v
Dewsbury-Batley : BB 9w, x
Wakefield : BB 9y, z
Huddersfield : BB 9aa, ab, ac, ad
Sheffield : BB 13a, b, c, d, e
Lincoln : BB 14 Combined sheet
Grimsby : BB 14e, f
Nottingham : BB 17 Combined sheet
Derby : BB 17c, d, e
Leicester : BB 17f, g
3. Book of photographs (12 March 1942, 66 pages)
Folder 7. [South Wales] Süd-Wales
1. 1:250,000 : Sheet 7, South Wales (August 1941)
2. Town plans 1:10,000 (Dated 30.xi.1941)
Swansea : BB 26 Combined sheet
Aberavon-Port Talbot : BB 26c, d
Newport : BB 27 Combined sheet
Cardiff : BB 32a, b, c
3. Book of photographs (30 November 1941, 39 pages)
Folder 8. Midlands
1. 1:250,000 : Sheet 8, Midlands (August 1941)
2. Town plans 1:10,000 (Dated 31.xii.1941)
Walsall : BB 17h, i, k, l
Dudley : BB 22a, b, c, d, e
Birmingham : BB 23a, b, c, d, e, f, g, h, i
Coventry : BB 23 Combined sheet
Rugby : BB 23m, n
Northampton : BB 23
Gloucester : BB 27g, h, i, k
Oxford : BB 28 (1. 8. 1941)
3. Book of photographs (7 October 1941, 35 pages)
Folder 9. [East Anglia] Ost-Anglia
1. 1:250,000 : Sheet 9, East Anglia (August 1941)
2. Town plans 1:10,000
Ipswich : BB 25 (1.8.1941)
3. Book of photographs (30 September 1941, 30 pages)
Folder 10. [England, South West] Südwest-England
1. 1:250,000 : Sheet 10, England, South West (August 1941)
2. Town plans 1:10,000 (Dated 1.8.1941)
Exeter : BB 35
Plymouth : BB 36
Torquay : BB 36
3. Book of photographs (18 September 1941, 24 pages)
Folder 11. [England, South] Süd-England
1. 1:250,000 : Sheet 11, England, South (August 1941)
2. Town plans 1:10,000 (Dated 1.8.1941)
Bath : BB 32
Bristol : BB 32
Bournemouth : BB 38
Portsmouth : BB 38
Southampton : BB 38
3. Book of photographs (5 October 1941, 35 pages)
Folder 12. [England, South East and London] Südost-England und London
1. 1:250,000 : Sheet 12, England, South East and London (August 1941)
2. Town plans 1:10,000 (Dated 1.8.1941)
Reading : BB 33
Brighton : BB 39
Dover : BB 40
Folkestone : BB 40
3. Book of photographs (2 October 1941, 66 pages)