S21 postcode district: Killamarsh and around, Derbyshire

S21 is a postcode district in Derbyshire, with 467 postcodes in use in 5 sectors. It has postcodes in Killamarsh and Eckington. It is split between 3 councils: North East Derbyshire (459 postcodes), Bolsover (7) and Chesterfield (1).

Postcodes in use: 467
Sectors: 5
Councils: 3 councils
Places: 2 places

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026. See all our data sources

Every postcode in S21, and which are new since 2020

New since 2020: 19
In use before 2020: 448
Outline: where 5 or more new postcodes since 2020 lie together

Of the 467 postcodes in S21 that ONS places, 19 are new since 2020 and 448 were in use before 2020.

Each mark is a postcode's centre point as ONS gives it, not a building. Press one to see its postcode and open its page. New since 2020 means it came into use in January 2020 or later. A dashed outline shows where 5 or more lie within 150 metres of each other. It is not a boundary, and no boundary is drawn. Where marks overlap, the one first in the key is drawn; the counts include every postcode.

The middle of its postcodes: latitude 53.3122, longitude -1.3390. Open this area on OpenStreetMap

Source: Office for National Statistics (ONS) Postcode Directory, August 2026, loaded 20 October 2026, the centre point of each postcode; when each came into use: the same directory; roads, rivers and built-up areas: Contains OS data © Crown copyright and database right 2026. Drawn by us. Street map: Ordnance Survey, OS Open Zoomstack, Open Government Licence v3.0, drawn with MapLibre. How we use them

The 5 newest postcodes

S21 1LXJune 2026 S21 1NNJune 2026 S21 1NJJanuary 2026 S21 1NLJanuary 2026 S21 1LGDecember 2025

Where the new postcodes lie together

6 new postcodes since 2020, outlined on the map. S21 1NN, is the newest of them.

What broadband can you get in S21?

Ofcom reports on 456 of the 467 postcodes in S21. At 319 of them every home and business can get gigabit broadband, and at 2 some cannot get decent broadband (10 Mbit/s).

Postcodes where every home can get gigabit319 of 456

Postcodes where every home can get superfast420 of 456

Postcodes where some cannot get decent broadband2 of 456

Ofcom gives each postcode's share of homes and businesses, not how many there are, so these count postcodes. Each postcode page has its own figures. A provider's checker answers for one address.

Check one address on Ofcom's checker

Source: Ofcom, Connected Nations, Spring 2026, data for January 2026, Open Government Licence v3.0. How we use it

Is S21 at risk of flooding?

36 of the 467 postcodes in S21 have a home or business in an area at risk of flooding from rivers or the sea, the Environment Agency says. At those, it puts 117 homes and businesses in an area at high or medium risk.

Homes and businesses in an area at risk, at 36 of 467 postcodes High: 68Medium: 49Low: 41Very low: 205

High: 3.3% or more a year (1 in 30). Medium: 1% to 3.3% a year. Low: 0.1% to 1% a year. Very low: under 0.1% a year (1 in 1,000). Each band is the chance of flooding in any one year.

Homes and businesses in an area at risk of flooding from rivers or the sea, as the Environment Agency counts them, added up over the postcodes. It is for the land, not each building, and leaves out surface water, groundwater and sewers. Each postcode page has its own figures and its flood warning areas.

Source: Environment Agency, Risk of Flooding from Rivers and Sea (postcodes in areas at risk), published 6 July 2026, Open Government Licence v3.0. How we use it

What do homes sell for in S21?

Homes in S21 sold for a typical £217,500 in the 12 months to August 2026, across 212 sales, up 11.3% on the 12 months before, HM Land Registry's figures show.

£217,500 typical price, the 12 months to August 2026

£195,500 12 months to August 2025

▲ up 11.3% on the 12 months before

Detached £306,250 78 sales
Semi-detached £185,000 79 sales
Terraced £166,250 42 sales
Flat or maisonette £120,000 13 sales

Each bar is that kind's typical price, against the most expensive kind here.

Standard sales of homes at market value. A typical price is the median, the middle sale. Sales take weeks to be registered, so the last month or two are incomplete. Each postcode page gives the figure for its own postcode sector.

Source: HM Land Registry Price Paid Data, files dated 28 September 2026. Contains HM Land Registry data © Crown copyright and database right 2021. This data is licensed under the Open Government Licence v3.0. How we use it