Cities, towns and villages
Situated just north of London, Hertfordshire is relatively affluent and suburban. The county is well-known for its commuters, i.e.: residents who work/study in London but wish to reside in a quieter environment outside of the capital. Hertfordshire has the third highest population density for a non-metropolitan county after Surrey and Berkshire which are similarly residential in nature. The region more or less fits the national average in terms of ethnic and religious diversity. However, the local district of Hertsmere has the highest percentage of Jewish residents (11% but much larger in certain towns such as Radlett) of any English district outside London. Despite Hertfordshire's current suburban status, it has a rich history and character. Topographically, Hertfordshire is agricultural and mostly consists of farmland (or in some areas, woodland) where there is no urban development.
The native Hertfordshire dialect (which to the untutored ear has a distinct west-country tinge) is virtually extinct, supplanted in the post-WW2 years by "Estuary English", a hybrid of various London accents and Received Pronunciation. This is because, in the post-WW2 years, more than 1 million people were moved from bomb-ravaged London to New Towns and expanded towns in the surrounding counties - a good many to Hertfordshire, meaning that accents in most of the Home Counties are now indistinguishable. English speakers (whether first or second-tongue) will have relatively little difficulty understanding it.
Hertfordshire is to the north of London and is easily accessible by train. Trains from London St Pancras International will take you to St Albans and Harpenden, from London King's Cross to Welwyn Garden City and Stevenage and trains from London Euston will stop in Watford and Hemel Hempstead.
Any of the major roads heading north out of London pass through Hertfordshire, principally the M1 (for west Herts), A1/A1(M) (for central Herts) and M11 (for east and north Herts). Watford and St Albans are about a 20 minute drive from Heathrow Airport around the M25 (clockwise), with the rest of the country easily reachable in another 10 minutes or so (all, of course, subject to congestion!).
Stansted Airport is about thirty minutes away from Hertford by car and connects to many international destinations, as well as to the train services offering connections to London or Cambridge.
Rail links, as mentioned, run north-south but there are no services running east-west across the county so the alternative is bus/coach travel or rental cars. There are many taxi services within the area. You can call them to get your destination. The very popular service is running in the UK, like UBER and click4cab. If you are in Hammersmith you can call Hammersmith Taxi and if you are in Colchester then you can call Colchester Taxis, if you are in Hertfordshire then you can call Ware Taxis. They are affordable services.
Warner Bros. Studios - Leavesden This film and media complex is owned by Warner Bros. and is one of the few places in the UK where notable films are made. Currently there is a studio tour running there dedicated to the making of Harry Potter. As the series was based at this site, the tour offers remarkable insight into its production. Memorable sets and props are all on display. Each tour lasts several hours and comes at a cost  except for children under 4 who go free.
Paradise Wildlife Park Very appealing for kids, the animal park boasts a diverse range of animals such as lemurs, white lions, jaguars, tapirs and wolves. The zoo is one of the most respected in Europe, establishing high standards for animal welfare and being heavily involved in conservation efforts.
The Natural History Museum - Tring This museum is free and is home to a rich collection of mounted specimens of mammals, birds, reptiles and insects - including extinct ones. Tring is also the town where George Washington's great-grandfather was born; more on this can be learned at the Tring Local History Museum, also free.
Henry Moore Studios and Gardens Around the village of Much Hadham is the artist Henry Moore's former home. At the site you can tour his home and the beautiful surrounding gardens, where his sculptures are also located for show. His last home here in Hertfordshire houses the most extensive range of his artwork. Adult and concessions ticket prices are between £5-7 a person, with cheaper prices for teens/children and under 5s go free.
Shaw's Corner Home of the Irish playwright George Bernard Shaw from 1906 until his death, it is now a museum. The place has largely been kept as the literary figure left it. The splendid gardens are also available to visit.
Hertford Hertford is Hertfordshire's county town and has retained much of its historical character. As such, the has a Heritage Trail, with blue plaques installed at its sites of interest. Many important sites are marked by this Trail, such as Hertford Castle, the Hertford Museum (free), the Corn Exchange, the statue of Samuel Stone and Hertford's Quaker Meeting House, the oldest Quaker meeting house globally. The Trail itself is free and self-guided using a published online map.
St Albans Once called Verulamium, St Albans city is noted for its rich Roman heritage. It is named after the martyr St Alban, a Christian convert who was from the city and was executed for refusing to submit to Roman paganism. The Verulamium Museum delves into this part of St Albans' history and displays artefacts, at a small cost to non-locals. Furthermore, you can opt to visit the local Roman theatre ruins  and the Roman Wall of St Albans, remnants of the wall Romans built to defend the city. St Albans Cathedral is free and also an architectural icon worth visiting; its construction began nearly a thousand years ago using bricks left from when the city was a Roman settlement. The Cathedral organises an annual Alban Pilgrimage  event on the Saturday nearest to the 22nd June, commemorating St Alban's martyrdom.
Country homes There are countless country homes around England and so very many in Hertfordshire. A notable one is Knebworth House, also a concert venue and that hosts the recurring pop and rock themed Knebworth Festival. Freddie Mercury did his last live performance with his band here in 1986. Another is Hatfield House,  a fine example of Jacobean architecture and where Elizabeth I spent her childhood. Other examples include the Rothamsted Estate, a manor and estate significant in the realms of agriculture and biotechnology as it is the site where some of the oldest agricultural experiments globally still run today (e.g.: the Parkgrass Experiment).
Other points of interest The garden city concept pioneered in England during the 19th century. This concept first came to fruition in Hertfordshire (e.g.: Letchworth Garden City) and has since spread worldwide.
There is plenty to do and see in Hertfordshire, but one highly popular activity is watching sports. Local team Watford play at Vicarage Road in the town itself and will be in the Championship for the 2014/15 football league season. Saracens rugby team also play their home matches at Vicarage Road, whilst occasionally using Twickenham stadium for their larger matches.
Around Hertfordshire, there are plenty of other activities to undertake. Local business Supercar Experiences is an expert in providing a luxury car rental service to those who are interested in testing their driving abilities in some of the world's supercars. Whilst this is an activity for adults, there is plenty to keep the kids entertained as well.
There are several beautiful nature spots to enjoy in Hertfordshire, notably the Ashridge Estate. This is a 5000-acre site full of woodland, grassland and a variety of wildlife including deer, muntjac and bluebells. It is free and very popular for walking, hiking and cycling. In the Estate, you can also pass Ashridge House, which Henry VIII once owned and where Elizabeth I had lived.
St Albans has perhaps the greatest variety of eating choices. Ye Olde Fighting Cocks is one of the few pubs in England that claim to be the oldest nationally. It is certainly charming and is conveniently a few minutes' walk of St Albans Cathedral. Meals are served here as well as drinks, although like any pub, they tend to offer a quintessentially English menu - pies, fish and chips, soup. There are very many pubs to choose from in the area and beyond, however.
Other recommendable local restaurant chains around the county include Loch Fyne (seafood), Wagamama (Japanese), Café Rouge (French-style) and Bella Italia (Italian-style). Curry houses also tend to deliver extremely well if you enjoy Indian-influenced cuisine.
The  Riverside Garden Centre in Hertford has a fantastic restaurant by the river side which serves a superb selection of meals to set the tastebuds racing. From a magnificent traditional English breakfast to light lunches, hot and cold snacks, excellent main meals to fresh cream teas.
Hertfordshire is one of the safest counties in Britain. The chances of you being attacked or robbed at night are slim, and in the daytime basically none. The only crime you may encounter is at closing time in the larger areas (Watford, St Albans, Hatfield and Stevenage) around clubs and pubs. Theft or interference with cars may occur, but only if left in the more unpleasant areas overnight.
The usual instructions apply: if a crime/emergency is in progress call 999 or 112 and ask for Police/Fire/Ambulance as needed. There are main police stations (generally open 9-5) in Watford, St Albans, Hatfield and Stevenage and smaller ones in all the other towns.
Hospitals (with A+E) in Welwyn Garden City (QEII), Stevenage (Lister), St Albans (St Albans City) and Watford (Watford General).