Hi Vernon,

Although you don't need to worry about the gender of most towns or cities in the expression , 'Venir de', as in the case of single word places it will always be

Je viens de Paris, je viens de Londres, je viens d'Amsterdam, je viens de Nice ...

In the case of towns which use an article in their name it will be,

je viens du Havre (because the town is Le Havre )

Je viens de La Rochelle ( because the town is La Rochelle)  

je viens des Sables d'Olonne ( the town is Les Sables d'Olonne) etc...

When you start talking about towns and cities or describing them you will need to use a gender and some will be feminine or masculine. Some will have an article in front of them like, La Havane , La Rochelle, Le Creusot which will determine whether they are feminine or masculine. Some will have an adjective in their name like, Mantes-la-Jolie which will indicate their gender. But in the majority of single word cases, there are no rules to indicate whether a city or town is masculine or feminine except when you use the adjectives 'vieux', 'grand', 'nouveau' or 'tout' in front of  them which  will always be masculine in this case, e.g. Le Vieux Nice, le grand Bruxelles, le nouveau Belleville, Le tout-Paris...

Hope this helps!