One of the great rivers of France is the Loire, famed for the châteaux along its verdant valley. In its course of 1,000 kilometres, it almost completely crosses this huge country from east to west.

But if La Loire is the queen of French rivers, then north of its lower reaches (a hop over the Channel for us) is a less known but worthy little prince – Le Loir – at 311 kilometres.

Rising near Chartres, it courses lazily through pretty, award-winning, and flower-bedecked villages, and a series of towns full of history – Vendôme, Montoire-sur-le-Loir, La Chartre-sur-le-Loir, Chateau du Loir, Le Lude, La Flèche and Durtal – before skirting Le Mans and eventually merging into the tributary complex of the grand dame Loire itself.

This little prince Loir closets its own display of "crown jewels", most of them squeezable into a four-day visit, though you may be tempted to spend longer.

Véronique Richard of the regional tourist board points out defiantly: "Yes, the châteaux of La Loire are wonderful, but they are relatively few and tend to be unfurnished. Here in Le Loir, our châteaux are much older – 12th and 13th century rather than 17th or 18th. If we include our manoirs and large houses, we can count about 500, many of them furnished and lived in, so I think they are more interesting." Straddling both eras is the magnificent château at Le Lude. Once a medieval fortress, today it's the home of a count and his family who open its doors to the public during the summer for guided tours, music recitals and special events. You can even try your hand at jam-making in its huge cellar kitchens.

The château and its setting in immaculate gardens sweeping down to the Loir can be admired, too, from the air during short sightseeing flights from about 20 euros per person for 15 minutes from the nearby airfield at La Flèche.

Towering dramatically above Lavardin, dubbed one of France's most beautiful villages and a treasure trove of history, is the stark silhouette of its ruined 11th-century château. Ownership was long disputed by the opposing armies of France and England, who were knocking "sept cloches" out of each other for about 100 years. Richard the Lionheart was here.

La Possonniere at Couture sur le Loir is a 15th-century, relatively plain manor house with exotic connections. It was the birthplace in 1524 of Pierre de Ronsard, chief romantic poet of the Renaissance, whose name is given famously to a rose.

Only traces remain of the medieval living quarters but, as expected, the rose garden attached to the house is a joy for thousands of visitors.

Regular features along the Loir are old mills which once took power from its waters. Some have been tastefully converted into gites and B&Bs, well worth seeking out as a different place to stay.

This being France, seek out local cuisine, including "black fowl" capon, a traditional breed noted for its quality and associated with La Flèche. You're on a river – look for freshwater fish such as zander, trout, pike and perch. Jasnières and Coteaux du Loir wines – ranging through white, gris ("grey") and rosé to red are from local, south-facing vineyards claimed to be uniquely rich in flint clay. Notable cheeses include Trefle, Petit Vendôme and Petit Trôo.

Finally, point scoring. Watch out for locals claiming their Loir as the longest river in France – which is plainly not so.

What they mean is it's the longest "rivière" – in French, a tributary. A river proper is a "fleuve", which by definition must end up in the sea, as the Loire does.

Factfile: Getting there: Brittany Ferries (www.brittanyferries.com) to St Malo, Le Havre or Caen. A four- hour drive to Vendôme on the Route Nationale N10 – worth exploring and a good starting point. Alternatively, Vendôme is a mere 40 minutes from Paris by TGV, then hire a car.

Places to stay: Moulin Frabault (Madame Stéphanie Ginisty) in Vendôme (02 54 73 16 58, www.vendome41.com), arty mill conversion – doubles from 68 euros including breakfast; candlelit dinner (superbly cooked and presented) romantically set on the riverbank, 30 euros per person excluding wine. Le Grand Moulin (Madame Daniele Millet- Lecourt) at La Chartre sur Loir (02 43 44 65 78), B&B and family gites newly and tastefully converted from an 18th-century mill in the heart of the town but secluded. Château de Chambiers (Monsieur et Madame Elie Crouan) near Durtal (02 41 76 07 31), antiques and four-posters furnish the rooms in this comfortable, 18th-century family home. Doubles from 90 euros including breakfast. Dinner from 28 euros served by the owners on the terrace.

For more details, call 0243 38 16 60 or visit the websites which are at www.vallee-du-loir.com, www.tourisme-paysflechois.fr or www.franceguide.com or email the French tourist office at info.uk@franceguide.com