The word sanct was introduced by Dante McCallavre to signify what he saw as "the only place where it is both possible to experiment freely with new forms of not only governance but human society in general, and the only place where a truly developed society can be maintained without external influence". The technical definition is a city on the deep ocean - blue-water zone - with a permanent population numbering at least in the thousands, and a government as independent from any grounded authority as possible.
Most of the population of the Duchy of Straylight is based permanently on sancts. However, Sundersprites, timesharers, expatriates with Straylightian citizenship residing in other duchies, people living on smaller platforms around coasts not classified as sancts, and various other classes are also significant enough to altogether make up over a third of the Straylightian population.
Sancts, being built to order and often advertised as a place to live for select groups of people, tend to develop rich and idiosyncratic local character. Beside history the greatest source of culture tends to be the local leader: Fresh counts often work to transform the sanct they lord over into whatever society they're interested in; in the Straylightian spirit (and the pursuit of interestingness), the Duchal government does what it can to support such projects. Furthermore the Dukal government can quite easily be convinced to subsidise the construction of completely new sancts.
- The largest sanct and economic center of Straylight. Discontinuity is currently the only sanct based on a breakwater design rather than the more common spar design, and the one with the largest OTEC power plant. Currently ruled by Count Icebreaker.
- A competitor to Discontinuity in the departments of population and economic activity. Currently ruled by an administrative council under the Pohjanvälke Coalition - apply to Duke for position of count.
- A disparate sanct borne out of the merger of four smaller ones, home to several cultural traditions and languages. Currently ruled by Count Corey.
- An economic alliance between a surface sanct with heavy industry, and an undersea city acting as a base for several seafloor mining operations. Currently an autonomous citystate with COSAC ties - apply to Duke for position of count.
- A relatively poor and crowded sanct specialising in mariculture for its economy. Currently a citystate participating in COSAC - apply to Duke for position of count.
- Much Rejoicing
- A less crowded version of Sargassum that comes with less maricultural diversity and more governmental instability. Currently ruled by a clique of local plutocrats - apply to Duke for position of count.
- Backbone Site
- A sanct packed to the brim with engineers, and home of Straylight's largest network exchange point. Currently ruled by Count Bayen.
- Unspeakable Horror
- A sanct famous for being absolutely devoid of character; The original name of Smaugaria has long since been supplanted by the nickname coined by a previous artistically inclined duke. Currently a citystate participating in COSAC - apply to Duke for position of count.
- Deep Trouble
- The oldest sanct currently afloat. Home to many projects in the field of human enhancement. Currently ruled by Count Scott.
- Sanctuary Dome
- Straylight's biggest tourist trap, especially popular with college-age Brookshirithians. Considered tacky in the extreme, and by some, a disgrace to its name. Currently a citystate participating in COSAC - apply to Duke for position of count.
- Wave Manifold
- A relatively minor sanct whose greatest claims to fame are the the long line of mathematicians who have got their education here, and the distinctive architectural style based on geometric shapes and waves. Currently ruled by an administrative council under the Pohjanvälke Coalition - apply to Duke for position of count.
- A cloistered cult-like community based around a religion that's a distant outgrowth of Horus worship in the Grand Commonwealth. Currently an autonomous theocratic citystate - apply to Duke for position of count.
- . Apply to Duke for position of count.
- Incremental Search
- The largest of the bay-based sancts. These days, largely a bedroom community for Yardistanis with a mariner's spirit or just plenty of money. Currently ruled by an administrative representative of the Pohjanvälke Coalition - apply to Duke for position of count.
- Discontinuity: 278 430
- Gensym: 83 142
- McCallavre: 55 672
- Pohjankaupunki: 39 439
- Sargassum: 32 043
- Much Rejoicing: 26 891
- Backbone Site: 23 710
- Unspeakable Horror: 23 103
- Deep Trouble: 20 004
- Sanctuary Dome: 15 822
- Wave Manifold: 15 285
- Clonmacnoise: 13 591
- Blavatsky: 11 853
- Incremental Search: 4 549